{"id":27330,"date":"2025-04-21T14:09:32","date_gmt":"2025-04-21T07:09:32","guid":{"rendered":"https:\/\/interdata.vn\/blog\/?p=27330"},"modified":"2025-04-21T14:15:08","modified_gmt":"2025-04-21T07:15:08","slug":"queue-la-gi","status":"publish","type":"post","link":"https:\/\/interdata.vn\/blog\/queue-la-gi\/","title":{"rendered":"Queue l\u00e0 g\u00ec? Gi\u1ea3i th\u00edch c\u1ea5u tr\u00fac d\u1eef li\u1ec7u h\u00e0ng \u0111\u1ee3i &#038; FIFO"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-white ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">N\u1ed8I DUNG<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-toggle-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Queue-la-gi\" >Queue l\u00e0 g\u00ec?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Nguyen-tac-%E2%80%9CVao-truoc-%E2%80%93-Ra-truoc%E2%80%9D-FIFO-%E2%80%93-First-In-First-Out-hoat-dong-nhu-the-nao\" >Nguy\u00ean t\u1eafc &#8220;V\u00e0o tr\u01b0\u1edbc &#8211; Ra tr\u01b0\u1edbc&#8221; (FIFO &#8211; First-In, First-Out) ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Minh-hoa-Queue-bang-vi-du-trong-doi-song-thuc-te\" >Minh h\u1ecda Queue b\u1eb1ng v\u00ed d\u1ee5 trong \u0111\u1eddi s\u1ed1ng th\u1ef1c t\u1ebf<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Cac-thao-tac-co-ban-tren-Queue\" >C\u00e1c thao t\u00e1c c\u01a1 b\u1ea3n tr\u00ean Queue<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Enqueue-Them-mot-phan-tu-vao-cuoi-hang-doi\" >Enqueue: Th\u00eam m\u1ed9t ph\u1ea7n t\u1eed v\u00e0o cu\u1ed1i h\u00e0ng \u0111\u1ee3i<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Dequeue-Lay-va-xoa-phan-tu-o-dau-hang-doi\" >Dequeue: L\u1ea5y v\u00e0 x\u00f3a ph\u1ea7n t\u1eed \u1edf \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Peek-Front-Xem-khong-xoa-phan-tu-o-dau-hang-doi\" >Peek \/ Front: Xem (kh\u00f4ng x\u00f3a) ph\u1ea7n t\u1eed \u1edf \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Cac-thao-tac-kiem-tra-khac-isEmpty-kiem-tra-rong-size-lay-kich-thuoc\" >C\u00e1c thao t\u00e1c ki\u1ec3m tra kh\u00e1c: isEmpty (ki\u1ec3m tra r\u1ed7ng), size (l\u1ea5y k\u00edch th\u01b0\u1edbc)<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Cach-trien-khai-Queue-pho-bien\" >C\u00e1ch tri\u1ec3n khai Queue ph\u1ed5 bi\u1ebfn<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Su-dung-Mang-Array-de-trien-khai-Queue\" >S\u1eed d\u1ee5ng M\u1ea3ng (Array) \u0111\u1ec3 tri\u1ec3n khai Queue<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Su-dung-Danh-sach-lien-ket-Linked-List-de-trien-khai-Queue\" >S\u1eed d\u1ee5ng Danh s\u00e1ch li\u00ean k\u1ebft (Linked List) \u0111\u1ec3 tri\u1ec3n khai Queue<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Su-dung-cac-thu-vien-Queue-co-san-trong-ngon-ngu-lap-trinh\" >S\u1eed d\u1ee5ng c\u00e1c th\u01b0 vi\u1ec7n Queue c\u00f3 s\u1eb5n trong ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Ung-dung-quan-trong-cua-Queue-trong-Lap-trinh-va-He-thong\" >\u1ee8ng d\u1ee5ng quan tr\u1ecdng c\u1ee7a Queue trong L\u1eadp tr\u00ecnh v\u00e0 H\u1ec7 th\u1ed1ng<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Lap-lich-tac-vu-Task-Scheduling-trong-He-dieu-hanh\" >L\u1eadp l\u1ecbch t\u00e1c v\u1ee5 (Task Scheduling) trong H\u1ec7 \u0111i\u1ec1u h\u00e0nh<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Thuat-toan-Tim-kiem-theo-chieu-rong-BFS-%E2%80%93-Breadth-First-Search\" >Thu\u1eadt to\u00e1n T\u00ecm ki\u1ebfm theo chi\u1ec1u r\u1ed9ng (BFS &#8211; Breadth-First Search)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Quan-ly-Bo-dem-Buffers-trong-xu-ly-luong-du-lieu-IO\" >Qu\u1ea3n l\u00fd B\u1ed9 \u0111\u1ec7m (Buffers) trong x\u1eed l\u00fd lu\u1ed3ng d\u1eef li\u1ec7u (I\/O)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Xu-ly-yeu-cau-theo-thu-tu-Vi-du-Hang-doi-tin-nhan-%E2%80%93-Message-Queue\" >X\u1eed l\u00fd y\u00eau c\u1ea7u theo th\u1ee9 t\u1ef1 (V\u00ed d\u1ee5: H\u00e0ng \u0111\u1ee3i tin nh\u1eafn &#8211; Message Queue)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Mo-phong-he-thong-doi-Vi-du-Quay-dich-vu-khach-hang\" >M\u00f4 ph\u1ecfng h\u1ec7 th\u1ed1ng \u0111\u1ee3i (V\u00ed d\u1ee5: Qu\u1ea7y d\u1ecbch v\u1ee5 kh\u00e1ch h\u00e0ng)<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#So-sanh-chi-tiet-giua-Queue-va-Stack\" >So s\u00e1nh chi ti\u1ebft gi\u1eefa Queue v\u00e0 Stack<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Diem-giong-nhau-co-ban\" >\u0110i\u1ec3m gi\u1ed1ng nhau c\u01a1 b\u1ea3n<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Khac-biet-cot-loi-Nguyen-tac-FIFO-vs-LIFO\" >Kh\u00e1c bi\u1ec7t c\u1ed1t l\u00f5i: Nguy\u00ean t\u1eafc FIFO vs LIFO<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Truong-hop-su-dung-dien-hinh-cua-tung-loai\" >Tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng \u0111i\u1ec3n h\u00ecnh c\u1ee7a t\u1eebng lo\u1ea1i<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Cac-bien-the-cua-Queue\" >C\u00e1c bi\u1ebfn th\u1ec3 c\u1ee7a Queue<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-24\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Hang-doi-uu-tien-Priority-Queue-Phan-tu-quan-trong-ra-truoc\" >H\u00e0ng \u0111\u1ee3i \u01b0u ti\u00ean (Priority Queue): Ph\u1ea7n t\u1eed quan tr\u1ecdng ra tr\u01b0\u1edbc<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-25\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Hang-doi-vong-Circular-Queue-Toi-uu-hoa-su-dung-bo-nho-mang\" >H\u00e0ng \u0111\u1ee3i v\u00f2ng (Circular Queue): T\u1ed1i \u01b0u h\u00f3a s\u1eed d\u1ee5ng b\u1ed9 nh\u1edb (m\u1ea3ng)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-26\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Deque-Double-Ended-Queue-Themxoa-o-ca-hai-dau\" >Deque (Double-Ended Queue): Th\u00eam\/x\u00f3a \u1edf c\u1ea3 hai \u0111\u1ea7u<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-27\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Cau-hoi-thuong-gap-ve-Queue-FAQ\" >C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p v\u1ec1 Queue (FAQ)<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-28\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Do-phuc-tap-thoi-gian-cua-Enqueue-Dequeue-Peek-la-bao-nhieu\" >\u0110\u1ed9 ph\u1ee9c t\u1ea1p th\u1eddi gian c\u1ee7a Enqueue, Dequeue, Peek l\u00e0 bao nhi\u00eau?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-29\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Khi-nao-thi-nen-chon-dung-Queue-thay-vi-Stack-hoac-cau-truc-du-lieu-khac\" >Khi n\u00e0o th\u00ec n\u00ean ch\u1ecdn d\u00f9ng Queue thay v\u00ec Stack ho\u1eb7c c\u1ea5u tr\u00fac d\u1eef li\u1ec7u kh\u00e1c?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-30\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Queue-co-bi-gioi-han-kich-thuoc-toi-da-khong\" >Queue c\u00f3 b\u1ecb gi\u1edbi h\u1ea1n k\u00edch th\u01b0\u1edbc t\u1ed1i \u0111a kh\u00f4ng?<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-31\" href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/#Khi-nao-ban-can-den-Queue\" >Khi n\u00e0o b\u1ea1n c\u1ea7n \u0111\u1ebfn Queue?<\/a><\/li><\/ul><\/nav><\/div>\n\n<p>B\u1ea1n c\u00f3 bao gi\u1edd th\u1eafc m\u1eafc c\u00e1ch m\u00e1y t\u00ednh x\u1eed l\u00fd c\u00f4ng vi\u1ec7c theo th\u1ee9 t\u1ef1, nh\u01b0 l\u1ec7nh in hay t\u00e1c v\u1ee5 h\u1ec7 th\u1ed1ng kh\u00f4ng? \u0110\u00f3 ch\u00ednh l\u00e0 l\u00fac c\u1ea5u tr\u00fac d\u1eef li\u1ec7u Queue (H\u00e0ng \u0111\u1ee3i) ph\u00e1t huy vai tr\u00f2 quan tr\u1ecdng v\u1edbi nguy\u00ean t\u1eafc FIFO. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd \u0111i s\u00e2u gi\u1ea3i th\u00edch Queue l\u00e0 g\u00ec, c\u00e1ch n\u00f3 ho\u1ea1t \u0111\u1ed9ng qua c\u00e1c thao t\u00e1c Enqueue\/Dequeue, ph\u01b0\u01a1ng ph\u00e1p tri\u1ec3n khai b\u1eb1ng code, c\u00e1c \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf v\u00e0 so s\u00e1nh n\u00f3 v\u1edbi Stack.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Queue-la-gi\"><\/span>Queue l\u00e0 g\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><a href=\"https:\/\/interdata.vn\/blog\/queue-la-gi\/\"><strong>Queue (hay H\u00e0ng \u0111\u1ee3i)<\/strong><\/a> l\u00e0 m\u1ed9t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u tuy\u1ebfn t\u00ednh c\u01a1 b\u1ea3n, ho\u1ea1t \u0111\u1ed9ng d\u1ef1a tr\u00ean nguy\u00ean t\u1eafc <strong>FIFO (First-In, First-Out)<\/strong>. \u0110i\u1ec1u n\u00e0y c\u00f3 ngh\u0129a l\u00e0 ph\u1ea7n t\u1eed n\u00e0o \u0111\u01b0\u1ee3c th\u00eam v\u00e0o h\u00e0ng \u0111\u1ee3i tr\u01b0\u1edbc (in) s\u1ebd l\u00e0 ph\u1ea7n t\u1eed \u0111\u01b0\u1ee3c x\u1eed l\u00fd v\u00e0 l\u1ea5y ra tr\u01b0\u1edbc ti\u00ean (out). Queue gi\u1ed1ng nh\u01b0 m\u1ed9t \u0111\u01b0\u1eddng \u1ed1ng n\u01a1i d\u1eef li\u1ec7u \u0111i v\u00e0o m\u1ed9t \u0111\u1ea7u v\u00e0 \u0111i ra \u1edf \u0111\u1ea7u kia theo \u0111\u00fang th\u1ee9 t\u1ef1 \u0111\u00e3 v\u00e0o.<\/p>\n<p>Queue \u0111\u01b0\u1ee3c xem l\u00e0 m\u1ed9t <strong>Ki\u1ec3u d\u1eef li\u1ec7u tr\u1eebu t\u01b0\u1ee3ng (Abstract Data Type &#8211; ADT)<\/strong>. \u0110i\u1ec1u n\u00e0y c\u00f3 ngh\u0129a l\u00e0 ch\u00fang ta t\u1eadp trung v\u00e0o <i>h\u00e0nh vi<\/i> (n\u00f3 l\u00e0m g\u00ec, c\u00e1c thao t\u00e1c n\u00f3 h\u1ed7 tr\u1ee3) h\u01a1n l\u00e0 <i>c\u00e1ch tri\u1ec3n khai<\/i> c\u1ee5 th\u1ec3 b\u00ean trong (n\u00f3 \u0111\u01b0\u1ee3c t\u1ea1o ra b\u1eb1ng g\u00ec &#8211; m\u1ea3ng hay danh s\u00e1ch li\u00ean k\u1ebft). Vi\u1ec7c \u0111\u1ecbnh ngh\u0129a Queue nh\u01b0 m\u1ed9t ADT gi\u00fap ch\u00fang ta t\u00e1ch bi\u1ec7t logic s\u1eed d\u1ee5ng v\u00e0 logic c\u00e0i \u0111\u1eb7t.<\/p>\n<p>Tr\u00e1i ng\u01b0\u1ee3c v\u1edbi Queue, m\u1ed9t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u tuy\u1ebfn t\u00ednh ph\u1ed5 bi\u1ebfn kh\u00e1c l\u00e0 <strong>Stack (Ng\u0103n x\u1ebfp)<\/strong>, ho\u1ea1t \u0111\u1ed9ng theo nguy\u00ean t\u1eafc <strong>LIFO (Last-In, First-Out)<\/strong> &#8211; v\u00e0o sau ra tr\u01b0\u1edbc. Vi\u1ec7c hi\u1ec3u r\u00f5 s\u1ef1 kh\u00e1c bi\u1ec7t n\u1ec1n t\u1ea3ng gi\u1eefa FIFO v\u00e0 LIFO l\u00e0 ch\u00eca kh\u00f3a \u0111\u1ec3 l\u1ef1a ch\u1ecdn \u0111\u00fang c\u1ea5u tr\u00fac d\u1eef li\u1ec7u cho b\u00e0i to\u00e1n c\u1ee5 th\u1ec3.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/queue-la-gi.jpg\" alt=\"queue l\u00e0 g\u00ec\" width=\"750\" height=\"500\" class=\"aligncenter size-full wp-image-27342\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/queue-la-gi.jpg 750w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/queue-la-gi-300x200.jpg 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n<h3><span class=\"ez-toc-section\" id=\"Nguyen-tac-%E2%80%9CVao-truoc-%E2%80%93-Ra-truoc%E2%80%9D-FIFO-%E2%80%93-First-In-First-Out-hoat-dong-nhu-the-nao\"><\/span>Nguy\u00ean t\u1eafc &#8220;V\u00e0o tr\u01b0\u1edbc &#8211; Ra tr\u01b0\u1edbc&#8221; (FIFO &#8211; First-In, First-Out) ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>FIFO (First-In, First-Out)<\/strong> l\u00e0 nguy\u00ean t\u1eafc n\u1ec1n t\u1ea3ng \u0111\u1ecbnh ngh\u0129a c\u00e1ch Queue ho\u1ea1t \u0111\u1ed9ng. N\u00f3 \u0111\u1ea3m b\u1ea3o t\u00ednh c\u00f4ng b\u1eb1ng v\u00e0 th\u1ee9 t\u1ef1 x\u1eed l\u00fd: ph\u1ea7n t\u1eed n\u00e0o \u0111\u1ebfn tr\u01b0\u1edbc s\u1ebd \u0111\u01b0\u1ee3c \u01b0u ti\u00ean ph\u1ee5c v\u1ee5 tr\u01b0\u1edbc. D\u1eef li\u1ec7u \u0111\u01b0\u1ee3c th\u00eam v\u00e0o m\u1ed9t \u0111\u1ea7u c\u1ee7a Queue (th\u01b0\u1eddng g\u1ecdi l\u00e0 <strong>Rear<\/strong> ho\u1eb7c <strong>Tail<\/strong> &#8211; cu\u1ed1i h\u00e0ng) v\u00e0 \u0111\u01b0\u1ee3c l\u1ea5y ra t\u1eeb \u0111\u1ea7u kia (th\u01b0\u1eddng g\u1ecdi l\u00e0 <strong>Front<\/strong> ho\u1eb7c <strong>Head<\/strong> &#8211; \u0111\u1ea7u h\u00e0ng).<\/p>\n<p>H\u00e3y h\u00ecnh dung qu\u00e1 tr\u00ecnh n\u00e0y nh\u01b0 m\u1ed9t d\u00f2ng ng\u01b0\u1eddi x\u1ebfp h\u00e0ng. Ng\u01b0\u1eddi m\u1edbi \u0111\u1ebfn s\u1ebd \u0111\u1ee9ng v\u00e0o cu\u1ed1i h\u00e0ng (Rear\/Tail). Ng\u01b0\u1eddi \u0111\u1ee9ng \u0111\u1ea7u h\u00e0ng (Front\/Head) l\u00e0 ng\u01b0\u1eddi \u0111\u00e3 ch\u1edd l\u00e2u nh\u1ea5t v\u00e0 s\u1ebd l\u00e0 ng\u01b0\u1eddi ti\u1ebfp theo \u0111\u01b0\u1ee3c ph\u1ee5c v\u1ee5 (l\u1ea5y ra kh\u1ecfi h\u00e0ng). Kh\u00f4ng c\u00f3 chuy\u1ec7n chen ngang hay ng\u01b0\u1eddi \u0111\u1ebfn sau \u0111\u01b0\u1ee3c x\u1eed l\u00fd tr\u01b0\u1edbc ng\u01b0\u1eddi \u0111\u1ebfn tr\u01b0\u1edbc.<\/p>\n<p>Nguy\u00ean t\u1eafc FIFO \u0111\u1ea3m b\u1ea3o th\u1ee9 t\u1ef1 c\u00e1c ph\u1ea7n t\u1eed \u0111\u01b0\u1ee3c b\u1ea3o to\u00e0n khi ch\u00fang \u0111i qua Queue. \u0110\u00e2y l\u00e0 \u0111\u1eb7c t\u00ednh quan tr\u1ecdng khi\u1ebfn Queue tr\u1edf n\u00ean h\u1eefu \u00edch trong c\u00e1c k\u1ecbch b\u1ea3n c\u1ea7n x\u1eed l\u00fd c\u00f4ng vi\u1ec7c ho\u1eb7c d\u1eef li\u1ec7u theo \u0111\u00fang tr\u00ecnh t\u1ef1 ch\u00fang \u0111\u01b0\u1ee3c nh\u1eadn. V\u00ed d\u1ee5, c\u00e1c y\u00eau c\u1ea7u g\u1eedi \u0111\u1ebfn m\u1ed9t m\u00e1y ch\u1ee7 web c\u1ea7n \u0111\u01b0\u1ee3c x\u1eed l\u00fd l\u1ea7n l\u01b0\u1ee3t theo th\u1ee9 t\u1ef1 ch\u00fang \u0111\u1ebfn.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Minh-hoa-Queue-bang-vi-du-trong-doi-song-thuc-te\"><\/span>Minh h\u1ecda Queue b\u1eb1ng v\u00ed d\u1ee5 trong \u0111\u1eddi s\u1ed1ng th\u1ef1c t\u1ebf<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Kh\u00e1i ni\u1ec7m Queue kh\u00f4ng h\u1ec1 xa l\u1ea1, n\u00f3 xu\u1ea5t hi\u1ec7n r\u1ea5t nhi\u1ec1u trong cu\u1ed9c s\u1ed1ng h\u00e0ng ng\u00e0y, gi\u00fap ch\u00fang ta d\u1ec5 d\u00e0ng h\u00ecnh dung nguy\u00ean t\u1eafc FIFO:<\/p>\n<ol>\n<li><strong>X\u1ebfp h\u00e0ng ch\u1edd thanh to\u00e1n:<\/strong> \u0110\u00e2y l\u00e0 v\u00ed d\u1ee5 kinh \u0111i\u1ec3n nh\u1ea5t. T\u1ea1i si\u00eau th\u1ecb, ng\u00e2n h\u00e0ng, hay r\u1ea1p chi\u1ebfu phim, m\u1ecdi ng\u01b0\u1eddi x\u1ebfp th\u00e0nh h\u00e0ng. Ai \u0111\u1ebfn tr\u01b0\u1edbc s\u1ebd \u0111\u01b0\u1ee3c ph\u1ee5c v\u1ee5 tr\u01b0\u1edbc. Ng\u01b0\u1eddi m\u1edbi \u0111\u1ebfn ph\u1ea3i \u0111\u1ee9ng v\u00e0o cu\u1ed1i h\u00e0ng.<\/li>\n<li><strong>H\u00e0ng \u0111\u1ee3i cu\u1ed9c g\u1ecdi t\u1ed5ng \u0111\u00e0i:<\/strong> Khi b\u1ea1n g\u1ecdi \u0111\u1ebfn m\u1ed9t t\u1ed5ng \u0111\u00e0i h\u1ed7 tr\u1ee3 v\u00e0 t\u1ea5t c\u1ea3 nh\u00e2n vi\u00ean \u0111\u1ec1u b\u1eadn, b\u1ea1n th\u01b0\u1eddng \u0111\u01b0\u1ee3c \u0111\u01b0a v\u00e0o m\u1ed9t h\u00e0ng \u0111\u1ee3i. H\u1ec7 th\u1ed1ng s\u1ebd k\u1ebft n\u1ed1i b\u1ea1n v\u1edbi nh\u00e2n vi\u00ean theo th\u1ee9 t\u1ef1 cu\u1ed9c g\u1ecdi \u0111\u1ebfn.<\/li>\n<li><strong>M\u00e1y in:<\/strong> Khi nhi\u1ec1u ng\u01b0\u1eddi c\u00f9ng g\u1eedi l\u1ec7nh in \u0111\u1ebfn m\u1ed9t m\u00e1y in d\u00f9ng chung, m\u00e1y in s\u1ebd t\u1ea1o m\u1ed9t h\u00e0ng \u0111\u1ee3i (print queue). C\u00e1c t\u00e0i li\u1ec7u s\u1ebd \u0111\u01b0\u1ee3c in ra theo \u0111\u00fang th\u1ee9 t\u1ef1 l\u1ec7nh in \u0111\u01b0\u1ee3c g\u1eedi \u0111\u1ebfn.<\/li>\n<li><strong>Qu\u1ea7y b\u00e1n v\u00e9:<\/strong> D\u00f9 l\u00e0 v\u00e9 xem phim, v\u00e9 t\u00e0u hay v\u00e9 xe bu\u00fdt, ng\u01b0\u1eddi mua th\u01b0\u1eddng ph\u1ea3i x\u1ebfp h\u00e0ng v\u00e0 ng\u01b0\u1eddi \u0111\u1ebfn tr\u01b0\u1edbc s\u1ebd mua \u0111\u01b0\u1ee3c v\u00e9 tr\u01b0\u1edbc.<\/li>\n<\/ol>\n<p>Nh\u1eefng v\u00ed d\u1ee5 n\u00e0y cho th\u1ea5y nguy\u00ean t\u1eafc FIFO r\u1ea5t t\u1ef1 nhi\u00ean v\u00e0 c\u00f4ng b\u1eb1ng trong vi\u1ec7c qu\u1ea3n l\u00fd th\u1ee9 t\u1ef1 truy c\u1eadp t\u00e0i nguy\u00ean ho\u1eb7c d\u1ecbch v\u1ee5 h\u1ea1n ch\u1ebf. Queue trong m\u00e1y t\u00ednh m\u00f4 ph\u1ecfng ch\u00ednh x\u00e1c c\u01a1 ch\u1ebf n\u00e0y \u0111\u1ec3 x\u1eed l\u00fd d\u1eef li\u1ec7u v\u00e0 t\u00e1c v\u1ee5 m\u1ed9t c\u00e1ch c\u00f3 tr\u1eadt t\u1ef1.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cac-thao-tac-co-ban-tren-Queue\"><\/span>C\u00e1c thao t\u00e1c c\u01a1 b\u1ea3n tr\u00ean Queue<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0110\u1ec3 s\u1eed d\u1ee5ng Queue hi\u1ec7u qu\u1ea3, ch\u00fang ta c\u1ea7n n\u1eafm v\u1eefng c\u00e1c thao t\u00e1c c\u01a1 b\u1ea3n m\u00e0 n\u00f3 h\u1ed7 tr\u1ee3. C\u00e1c thao t\u00e1c n\u00e0y \u0111\u1ecbnh ngh\u0129a c\u00e1ch ch\u00fang ta t\u01b0\u01a1ng t\u00e1c v\u1edbi d\u1eef li\u1ec7u trong h\u00e0ng \u0111\u1ee3i. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 nh\u1eefng thao t\u00e1c c\u1ed1t l\u00f5i:<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Enqueue-Them-mot-phan-tu-vao-cuoi-hang-doi\"><\/span>Enqueue: Th\u00eam m\u1ed9t ph\u1ea7n t\u1eed v\u00e0o cu\u1ed1i h\u00e0ng \u0111\u1ee3i<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Enqueue<\/strong> l\u00e0 thao t\u00e1c d\u00f9ng \u0111\u1ec3 th\u00eam m\u1ed9t ph\u1ea7n t\u1eed m\u1edbi v\u00e0o v\u1ecb tr\u00ed cu\u1ed1i c\u00f9ng (Rear\/Tail) c\u1ee7a Queue. Khi m\u1ed9t ph\u1ea7n t\u1eed \u0111\u01b0\u1ee3c <code>enqueue<\/code>, n\u00f3 s\u1ebd tr\u1edf th\u00e0nh ph\u1ea7n t\u1eed m\u1edbi nh\u1ea5t trong h\u00e0ng \u0111\u1ee3i v\u00e0 s\u1ebd ph\u1ea3i ch\u1edd t\u1ea5t c\u1ea3 c\u00e1c ph\u1ea7n t\u1eed ph\u00eda tr\u01b0\u1edbc n\u00f3 \u0111\u01b0\u1ee3c x\u1eed l\u00fd xong m\u1edbi \u0111\u1ebfn l\u01b0\u1ee3t m\u00ecnh.<\/p>\n<p>Thao t\u00e1c n\u00e0y gi\u1ed1ng nh\u01b0 h\u00e0nh \u0111\u1ed9ng m\u1ed9t ng\u01b0\u1eddi m\u1edbi \u0111\u1ebfn v\u00e0 \u0111\u1ee9ng v\u00e0o cu\u1ed1i h\u00e0ng ch\u1edd. N\u00f3 l\u00e0m t\u0103ng s\u1ed1 l\u01b0\u1ee3ng ph\u1ea7n t\u1eed trong Queue l\u00ean m\u1ed9t \u0111\u01a1n v\u1ecb. N\u1ebfu Queue \u0111\u01b0\u1ee3c tri\u1ec3n khai b\u1eb1ng m\u1ea3ng c\u00f3 k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh, thao t\u00e1c <code>enqueue<\/code> c\u1ea7n ki\u1ec3m tra xem Queue \u0111\u00e3 \u0111\u1ea7y ch\u01b0a tr\u01b0\u1edbc khi th\u00eam (tr\u00e1nh tr\u00e0n b\u1ed9 nh\u1edb &#8211; overflow).<\/p>\n<p>Trong h\u1ea7u h\u1ebft c\u00e1c c\u00e1ch tri\u1ec3n khai hi\u1ec7u qu\u1ea3 (v\u00ed d\u1ee5: d\u00f9ng danh s\u00e1ch li\u00ean k\u1ebft ho\u1eb7c m\u1ea3ng \u0111\u1ed9ng), \u0111\u1ed9 ph\u1ee9c t\u1ea1p th\u1eddi gian c\u1ee7a thao t\u00e1c <code>enqueue<\/code> th\u01b0\u1eddng l\u00e0 <strong>O(1)<\/strong>, ngh\u0129a l\u00e0 th\u1eddi gian th\u1ef1c hi\u1ec7n kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o s\u1ed1 l\u01b0\u1ee3ng ph\u1ea7n t\u1eed hi\u1ec7n c\u00f3 trong Queue.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Dequeue-Lay-va-xoa-phan-tu-o-dau-hang-doi\"><\/span>Dequeue: L\u1ea5y v\u00e0 x\u00f3a ph\u1ea7n t\u1eed \u1edf \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Dequeue<\/strong> l\u00e0 thao t\u00e1c d\u00f9ng \u0111\u1ec3 l\u1ea5y ra v\u00e0 \u0111\u1ed3ng th\u1eddi x\u00f3a b\u1ecf ph\u1ea7n t\u1eed \u1edf v\u1ecb tr\u00ed \u0111\u1ea7u ti\u00ean (Front\/Head) c\u1ee7a Queue. \u0110\u00e2y ch\u00ednh l\u00e0 ph\u1ea7n t\u1eed \u0111\u00e3 \u1edf trong h\u00e0ng \u0111\u1ee3i l\u00e2u nh\u1ea5t, tu\u00e2n th\u1ee7 \u0111\u00fang nguy\u00ean t\u1eafc FIFO. Sau khi <code>dequeue<\/code>, ph\u1ea7n t\u1eed ti\u1ebfp theo (n\u1ebfu c\u00f3) s\u1ebd tr\u1edf th\u00e0nh ph\u1ea7n t\u1eed \u0111\u1ea7u h\u00e0ng m\u1edbi.<\/p>\n<p>Thao t\u00e1c n\u00e0y t\u01b0\u01a1ng \u1ee9ng v\u1edbi vi\u1ec7c ng\u01b0\u1eddi \u0111\u1ee9ng \u0111\u1ea7u h\u00e0ng \u0111\u01b0\u1ee3c ph\u1ee5c v\u1ee5 v\u00e0 r\u1eddi \u0111i. N\u00f3 l\u00e0m gi\u1ea3m s\u1ed1 l\u01b0\u1ee3ng ph\u1ea7n t\u1eed trong Queue \u0111i m\u1ed9t \u0111\u01a1n v\u1ecb. Tr\u01b0\u1edbc khi th\u1ef1c hi\u1ec7n <code>dequeue<\/code>, c\u1ea7n ki\u1ec3m tra xem Queue c\u00f3 r\u1ed7ng kh\u00f4ng (tr\u00e1nh l\u1ed7i l\u1ea5y ph\u1ea7n t\u1eed t\u1eeb h\u00e0ng \u0111\u1ee3i r\u1ed7ng &#8211; underflow).<\/p>\n<p>T\u01b0\u01a1ng t\u1ef1 nh\u01b0 <code>enqueue<\/code>, \u0111\u1ed9 ph\u1ee9c t\u1ea1p th\u1eddi gian c\u1ee7a thao t\u00e1c <code>dequeue<\/code> trong c\u00e1c tri\u1ec3n khai hi\u1ec7u qu\u1ea3 c\u0169ng th\u01b0\u1eddng l\u00e0 <strong>O(1)<\/strong>. Vi\u1ec7c truy c\u1eadp v\u00e0 lo\u1ea1i b\u1ecf ph\u1ea7n t\u1eed \u0111\u1ea7u h\u00e0ng di\u1ec5n ra nhanh ch\u00f3ng.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Peek-Front-Xem-khong-xoa-phan-tu-o-dau-hang-doi\"><\/span>Peek \/ Front: Xem (kh\u00f4ng x\u00f3a) ph\u1ea7n t\u1eed \u1edf \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Peek<\/strong> (ho\u1eb7c <strong>Front<\/strong>) l\u00e0 thao t\u00e1c cho ph\u00e9p ch\u00fang ta xem gi\u00e1 tr\u1ecb c\u1ee7a ph\u1ea7n t\u1eed \u0111ang \u1edf \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i (Front\/Head) m\u00e0 <i>kh\u00f4ng<\/i> x\u00f3a n\u00f3 kh\u1ecfi Queue. Thao t\u00e1c n\u00e0y h\u1eefu \u00edch khi b\u1ea1n c\u1ea7n bi\u1ebft ph\u1ea7n t\u1eed n\u00e0o s\u1eafp \u0111\u01b0\u1ee3c x\u1eed l\u00fd ti\u1ebfp theo m\u00e0 kh\u00f4ng mu\u1ed1n thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i c\u1ee7a h\u00e0ng \u0111\u1ee3i.<\/p>\n<p>H\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng b\u1ea1n ch\u1ec9 li\u1ebfc nh\u00ecn ng\u01b0\u1eddi \u0111\u1ee9ng \u0111\u1ea7u h\u00e0ng \u0111\u1ec3 bi\u1ebft \u0111\u00f3 l\u00e0 ai, ch\u1ee9 kh\u00f4ng y\u00eau c\u1ea7u h\u1ecd r\u1eddi \u0111i. <code>Peek<\/code> kh\u00f4ng l\u00e0m thay \u0111\u1ed5i s\u1ed1 l\u01b0\u1ee3ng ph\u1ea7n t\u1eed hay v\u1ecb tr\u00ed c\u00e1c ph\u1ea7n t\u1eed trong Queue. Gi\u1ed1ng nh\u01b0 <code>dequeue<\/code>, c\u1ea7n ki\u1ec3m tra Queue c\u00f3 r\u1ed7ng kh\u00f4ng tr\u01b0\u1edbc khi th\u1ef1c hi\u1ec7n <code>peek<\/code>.<\/p>\n<p>\u0110\u1ed9 ph\u1ee9c t\u1ea1p th\u1eddi gian c\u1ee7a thao t\u00e1c <code>peek<\/code> c\u0169ng l\u00e0 <strong>O(1)<\/strong>, v\u00ec vi\u1ec7c truy c\u1eadp ph\u1ea7n t\u1eed \u0111\u1ea7u ti\u00ean r\u1ea5t nhanh ch\u00f3ng trong c\u00e1c c\u00e1ch tri\u1ec3n khai th\u00f4ng th\u01b0\u1eddng.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Cac-thao-tac-kiem-tra-khac-isEmpty-kiem-tra-rong-size-lay-kich-thuoc\"><\/span>C\u00e1c thao t\u00e1c ki\u1ec3m tra kh\u00e1c: isEmpty (ki\u1ec3m tra r\u1ed7ng), size (l\u1ea5y k\u00edch th\u01b0\u1edbc)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Ngo\u00e0i ba thao t\u00e1c c\u1ed1t l\u00f5i tr\u00ean, Queue th\u01b0\u1eddng cung c\u1ea5p th\u00eam m\u1ed9t s\u1ed1 thao t\u00e1c ph\u1ee5 tr\u1ee3 h\u1eefu \u00edch:<\/p>\n<ul>\n<li><strong>isEmpty():<\/strong> Ki\u1ec3m tra xem Queue c\u00f3 \u0111ang ch\u1ee9a ph\u1ea7n t\u1eed n\u00e0o kh\u00f4ng. Tr\u1ea3 v\u1ec1 <code>true<\/code> n\u1ebfu Queue r\u1ed7ng v\u00e0 <code>false<\/code> n\u1ebfu ng\u01b0\u1ee3c l\u1ea1i. Thao t\u00e1c n\u00e0y r\u1ea5t quan tr\u1ecdng \u0111\u1ec3 tr\u00e1nh l\u1ed7i underflow khi th\u1ef1c hi\u1ec7n <code>dequeue<\/code> ho\u1eb7c <code>peek<\/code>. \u0110\u1ed9 ph\u1ee9c t\u1ea1p l\u00e0 <strong>O(1)<\/strong>.<\/li>\n<li><strong>isFull() (T\u00f9y ch\u1ecdn):<\/strong> N\u1ebfu Queue \u0111\u01b0\u1ee3c tri\u1ec3n khai b\u1eb1ng m\u1ea3ng c\u00f3 k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh, thao t\u00e1c n\u00e0y d\u00f9ng \u0111\u1ec3 ki\u1ec3m tra xem Queue \u0111\u00e3 \u0111\u1ea7y hay ch\u01b0a. Tr\u1ea3 v\u1ec1 <code>true<\/code> n\u1ebfu \u0111\u1ea7y, <code>false<\/code> n\u1ebfu c\u00f2n ch\u1ed7. Quan tr\u1ecdng \u0111\u1ec3 tr\u00e1nh l\u1ed7i overflow khi <code>enqueue<\/code>. \u0110\u1ed9 ph\u1ee9c t\u1ea1p l\u00e0 <strong>O(1)<\/strong>.<\/li>\n<li><strong>size():<\/strong> Tr\u1ea3 v\u1ec1 s\u1ed1 l\u01b0\u1ee3ng ph\u1ea7n t\u1eed hi\u1ec7n c\u00f3 trong Queue. Gi\u00fap theo d\u00f5i t\u00ecnh tr\u1ea1ng c\u1ee7a h\u00e0ng \u0111\u1ee3i. \u0110\u1ed9 ph\u1ee9c t\u1ea1p c\u00f3 th\u1ec3 l\u00e0 <strong>O(1)<\/strong> (n\u1ebfu l\u01b0u tr\u1eef bi\u1ebfn \u0111\u1ebfm) ho\u1eb7c <strong>O(n)<\/strong> (n\u1ebfu ph\u1ea3i duy\u1ec7t qua \u0111\u1ec3 \u0111\u1ebfm, \u00edt ph\u1ed5 bi\u1ebfn h\u01a1n).<\/li>\n<\/ul>\n<p>Vi\u1ec7c hi\u1ec3u r\u00f5 v\u00e0 s\u1eed d\u1ee5ng \u0111\u00fang c\u00e1c thao t\u00e1c n\u00e0y l\u00e0 n\u1ec1n t\u1ea3ng \u0111\u1ec3 l\u00e0m vi\u1ec7c hi\u1ec7u qu\u1ea3 v\u1edbi c\u1ea5u tr\u00fac d\u1eef li\u1ec7u Queue trong c\u00e1c \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cach-trien-khai-Queue-pho-bien\"><\/span>C\u00e1ch tri\u1ec3n khai Queue ph\u1ed5 bi\u1ebfn<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>M\u1eb7c d\u00f9 Queue l\u00e0 m\u1ed9t ki\u1ec3u d\u1eef li\u1ec7u tr\u1eebu t\u01b0\u1ee3ng (ADT), \u0111\u1ec3 s\u1eed d\u1ee5ng n\u00f3 trong l\u1eadp tr\u00ecnh, ch\u00fang ta c\u1ea7n m\u1ed9t c\u00e1ch tri\u1ec3n khai c\u1ee5 th\u1ec3. C\u00f3 hai c\u00e1ch ch\u00ednh \u0111\u1ec3 hi\u1ec7n th\u1ef1c h\u00f3a Queue: s\u1eed d\u1ee5ng M\u1ea3ng (Array) ho\u1eb7c s\u1eed d\u1ee5ng Danh s\u00e1ch li\u00ean k\u1ebft (Linked List). Ngo\u00e0i ra, h\u1ea7u h\u1ebft c\u00e1c ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh hi\u1ec7n \u0111\u1ea1i \u0111\u1ec1u cung c\u1ea5p s\u1eb5n c\u00e1c th\u01b0 vi\u1ec7n Queue ti\u1ec7n l\u1ee3i.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-01.jpg\" alt=\"Queue 01\" width=\"750\" height=\"500\" class=\"aligncenter size-full wp-image-27339\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-01.jpg 750w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-01-300x200.jpg 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n<h3><span class=\"ez-toc-section\" id=\"Su-dung-Mang-Array-de-trien-khai-Queue\"><\/span>S\u1eed d\u1ee5ng M\u1ea3ng (Array) \u0111\u1ec3 tri\u1ec3n khai Queue<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Tri\u1ec3n khai Queue b\u1eb1ng m\u1ea3ng l\u00e0 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p kh\u00e1 tr\u1ef1c quan. Ch\u00fang ta s\u1eed d\u1ee5ng m\u1ed9t m\u1ea3ng c\u1ed1 \u0111\u1ecbnh ho\u1eb7c \u0111\u1ed9ng \u0111\u1ec3 l\u01b0u tr\u1eef c\u00e1c ph\u1ea7n t\u1eed c\u1ee7a Queue. C\u1ea7n th\u00eam hai bi\u1ebfn con tr\u1ecf (ho\u1eb7c ch\u1ec9 s\u1ed1): <code>front<\/code> \u0111\u1ec3 ch\u1ec9 v\u1ecb tr\u00ed ph\u1ea7n t\u1eed \u0111\u1ea7u h\u00e0ng v\u00e0 <code>rear<\/code> \u0111\u1ec3 ch\u1ec9 v\u1ecb tr\u00ed <i>ti\u1ebfp theo<\/i> s\u1ebd th\u00eam ph\u1ea7n t\u1eed m\u1edbi v\u00e0o (ho\u1eb7c v\u1ecb tr\u00ed ph\u1ea7n t\u1eed cu\u1ed1i c\u00f9ng, t\u00f9y quy \u01b0\u1edbc).<\/p>\n<p>Khi <code>enqueue<\/code>, ta th\u00eam ph\u1ea7n t\u1eed v\u00e0o v\u1ecb tr\u00ed <code>rear<\/code> v\u00e0 t\u0103ng <code>rear<\/code> l\u00ean 1. Khi <code>dequeue<\/code>, ta l\u1ea5y ph\u1ea7n t\u1eed t\u1ea1i v\u1ecb tr\u00ed <code>front<\/code> v\u00e0 t\u0103ng <code>front<\/code> l\u00ean 1. V\u1ea5n \u0111\u1ec1 n\u1ea3y sinh l\u00e0 khi <code>front<\/code> v\u00e0 <code>rear<\/code> ti\u1ebfn v\u1ec1 cu\u1ed1i m\u1ea3ng, ph\u1ea7n \u0111\u1ea7u m\u1ea3ng c\u00f3 th\u1ec3 c\u00f2n tr\u1ed1ng nh\u01b0ng kh\u00f4ng d\u00f9ng \u0111\u01b0\u1ee3c.<\/p>\n<p>\u0110\u1ec3 gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 n\u00e0y, ng\u01b0\u1eddi ta th\u01b0\u1eddng d\u00f9ng <strong>M\u1ea3ng v\u00f2ng (Circular Array)<\/strong>. Khi <code>rear<\/code> ho\u1eb7c <code>front<\/code> \u0111\u1ea1t \u0111\u1ebfn cu\u1ed1i m\u1ea3ng, n\u00f3 s\u1ebd &#8220;quay v\u00f2ng&#8221; l\u1ea1i v\u1ecb tr\u00ed \u0111\u1ea7u m\u1ea3ng (s\u1eed d\u1ee5ng ph\u00e9p to\u00e1n modulo <code>%<\/code>). \u0110i\u1ec1u n\u00e0y gi\u00fap t\u1eadn d\u1ee5ng t\u1ed1i \u0111a kh\u00f4ng gian c\u1ee7a m\u1ea3ng.<\/p>\n<p>Python<\/p>\n<pre><code class=\"language-plaintext\"># V\u00ed d\u1ee5 minh h\u1ecda tri\u1ec3n khai Queue b\u1eb1ng M\u1ea3ng v\u00f2ng Python (\u0111\u01a1n gi\u1ea3n)\r\nclass ArrayQueue:\r\n    def __init__(self, capacity):\r\n        self.capacity = capacity\r\n        self.queue = [None] * capacity\r\n        self.front = 0\r\n        self.rear = 0\r\n        self.size = 0\r\n\r\n    def is_empty(self):\r\n        return self.size == 0\r\n\r\n    def is_full(self):\r\n        return self.size == self.capacity\r\n\r\n    def enqueue(self, item):\r\n        if self.is_full():\r\n            print(\"L\u1ed7i: H\u00e0ng \u0111\u1ee3i \u0111\u1ea7y!\")\r\n            return\r\n        self.queue[self.rear] = item\r\n        self.rear = (self.rear + 1) % self.capacity # Quay v\u00f2ng\r\n        self.size += 1\r\n        print(f\"\u0110\u00e3 th\u00eam {item} v\u00e0o cu\u1ed1i h\u00e0ng \u0111\u1ee3i.\")\r\n\r\n    def dequeue(self):\r\n        if self.is_empty():\r\n            print(\"L\u1ed7i: H\u00e0ng \u0111\u1ee3i r\u1ed7ng!\")\r\n            return None\r\n        item = self.queue[self.front]\r\n        self.queue[self.front] = None # Optional: Clear the dequeued slot\r\n        self.front = (self.front + 1) % self.capacity # Quay v\u00f2ng\r\n        self.size -= 1\r\n        print(f\"\u0110\u00e3 l\u1ea5y {item} t\u1eeb \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i.\")\r\n        return item\r\n\r\n    def peek(self):\r\n        if self.is_empty():\r\n            print(\"L\u1ed7i: H\u00e0ng \u0111\u1ee3i r\u1ed7ng!\")\r\n            return None\r\n        return self.queue[self.front]\r\n\r\n    def display(self):\r\n        print(\"Tr\u1ea1ng th\u00e1i h\u00e0ng \u0111\u1ee3i (t\u1eeb Front \u0111\u1ebfn Rear):\")\r\n        if self.is_empty():\r\n            print(\"R\u1ed7ng\")\r\n            return\r\n        # In theo th\u1ee9 t\u1ef1 logic t\u1eeb front\r\n        idx = self.front\r\n        for _ in range(self.size):\r\n             print(self.queue[idx], end=\" &lt;- \")\r\n             idx = (idx + 1) % self.capacity\r\n        print(\" (End)\")\r\n\r\n# S\u1eed d\u1ee5ng th\u1eed\r\nq_arr = ArrayQueue(5)\r\nq_arr.enqueue(10)\r\nq_arr.enqueue(20)\r\nq_arr.enqueue(30)\r\nq_arr.display()\r\nprint(\"Ph\u1ea7n t\u1eed \u0111\u1ea7u:\", q_arr.peek())\r\nq_arr.dequeue()\r\nq_arr.display()\r\nq_arr.enqueue(40)\r\nq_arr.enqueue(50)\r\nq_arr.enqueue(60) # S\u1ebd b\u00e1o \u0111\u1ea7y\r\nq_arr.display()\r\nq_arr.dequeue()\r\nq_arr.dequeue()\r\nq_arr.enqueue(70)\r\nq_arr.display()\r\n<\/code><\/pre>\n<h4>\u01afu \u0111i\u1ec3m v\u00e0 Nh\u01b0\u1ee3c \u0111i\u1ec3m (M\u1ea3ng)<\/h4>\n<ul>\n<li><strong>\u01afu \u0111i\u1ec3m:<\/strong>\n<ul>\n<li>Truy c\u1eadp ph\u1ea7n t\u1eed nhanh (O(1)) n\u1ebfu bi\u1ebft ch\u1ec9 s\u1ed1 (d\u00f9 \u00edt d\u00f9ng tr\u1ef1c ti\u1ebfp trong Queue).<\/li>\n<li>Qu\u1ea3n l\u00fd b\u1ed9 nh\u1edb \u0111\u01a1n gi\u1ea3n h\u01a1n (kh\u1ed1i b\u1ed9 nh\u1edb li\u1ec1n k\u1ec1).<\/li>\n<li>Hi\u1ec7u qu\u1ea3 v\u1ec1 b\u1ed9 nh\u1edb cache do t\u00ednh li\u1ec1n k\u1ec1.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Nh\u01b0\u1ee3c \u0111i\u1ec3m:<\/strong>\n<ul>\n<li>K\u00edch th\u01b0\u1edbc th\u01b0\u1eddng c\u1ed1 \u0111\u1ecbnh (v\u1edbi m\u1ea3ng t\u0129nh) ho\u1eb7c vi\u1ec7c thay \u0111\u1ed5i k\u00edch th\u01b0\u1edbc (m\u1ea3ng \u0111\u1ed9ng) t\u1ed1n k\u00e9m (O(n)).<\/li>\n<li>C\u00f3 th\u1ec3 l\u00e3ng ph\u00ed b\u1ed9 nh\u1edb n\u1ebfu kh\u00f4ng d\u00f9ng h\u1ebft dung l\u01b0\u1ee3ng m\u1ea3ng.<\/li>\n<li>C\u1ea7n x\u1eed l\u00fd logic quay v\u00f2ng ph\u1ee9c t\u1ea1p h\u01a1n m\u1ed9t ch\u00fat (v\u1edbi m\u1ea3ng v\u00f2ng).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Su-dung-Danh-sach-lien-ket-Linked-List-de-trien-khai-Queue\"><\/span>S\u1eed d\u1ee5ng Danh s\u00e1ch li\u00ean k\u1ebft (Linked List) \u0111\u1ec3 tri\u1ec3n khai Queue<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Tri\u1ec3n khai Queue b\u1eb1ng <strong>Danh s\u00e1ch li\u00ean k\u1ebft (Linked List)<\/strong> kh\u1eafc ph\u1ee5c \u0111\u01b0\u1ee3c nh\u01b0\u1ee3c \u0111i\u1ec3m v\u1ec1 k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh c\u1ee7a m\u1ea3ng. M\u1ed7i ph\u1ea7n t\u1eed trong Queue l\u00e0 m\u1ed9t <strong>n\u00fat (node)<\/strong>, ch\u1ee9a d\u1eef li\u1ec7u v\u00e0 m\u1ed9t con tr\u1ecf (<code>next<\/code>) tr\u1ecf \u0111\u1ebfn n\u00fat ti\u1ebfp theo. Ch\u00fang ta c\u1ea7n hai con tr\u1ecf ch\u00ednh: <code>front<\/code> tr\u1ecf \u0111\u1ebfn n\u00fat \u0111\u1ea7u ti\u00ean v\u00e0 <code>rear<\/code> tr\u1ecf \u0111\u1ebfn n\u00fat cu\u1ed1i c\u00f9ng.<\/p>\n<p>Khi <code>enqueue<\/code>, m\u1ed9t n\u00fat m\u1edbi \u0111\u01b0\u1ee3c t\u1ea1o. Con tr\u1ecf <code>next<\/code> c\u1ee7a n\u00fat <code>rear<\/code> hi\u1ec7n t\u1ea1i s\u1ebd tr\u1ecf \u0111\u1ebfn n\u00fat m\u1edbi n\u00e0y, v\u00e0 con tr\u1ecf <code>rear<\/code> \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt \u0111\u1ec3 tr\u1ecf \u0111\u1ebfn n\u00fat m\u1edbi. N\u1ebfu Queue r\u1ed7ng, c\u1ea3 <code>front<\/code> v\u00e0 <code>rear<\/code> \u0111\u1ec1u tr\u1ecf \u0111\u1ebfn n\u00fat m\u1edbi.<\/p>\n<p>Khi <code>dequeue<\/code>, ta l\u1ea5y d\u1eef li\u1ec7u t\u1eeb n\u00fat <code>front<\/code>, sau \u0111\u00f3 c\u1eadp nh\u1eadt con tr\u1ecf <code>front<\/code> \u0111\u1ec3 tr\u1ecf \u0111\u1ebfn n\u00fat ti\u1ebfp theo (<code>front.next<\/code>). N\u1ebfu sau khi <code>dequeue<\/code> m\u00e0 Queue tr\u1edf n\u00ean r\u1ed7ng, <code>rear<\/code> c\u0169ng c\u1ea7n \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt th\u00e0nh <code>None<\/code>.<\/p>\n<p>Python<\/p>\n<pre><code class=\"language-plaintext\"># V\u00ed d\u1ee5 minh h\u1ecda tri\u1ec3n khai Queue b\u1eb1ng Linked List Python\r\nclass Node:\r\n    def __init__(self, data):\r\n        self.data = data\r\n        self.next = None\r\n\r\nclass LinkedListQueue:\r\n    def __init__(self):\r\n        self.front = None\r\n        self.rear = None\r\n        self.size = 0\r\n\r\n    def is_empty(self):\r\n        return self.size == 0\r\n\r\n    def enqueue(self, item):\r\n        new_node = Node(item)\r\n        if self.is_empty():\r\n            self.front = new_node\r\n            self.rear = new_node\r\n        else:\r\n            self.rear.next = new_node\r\n            self.rear = new_node\r\n        self.size += 1\r\n        print(f\"\u0110\u00e3 th\u00eam {item} v\u00e0o cu\u1ed1i h\u00e0ng \u0111\u1ee3i.\")\r\n\r\n    def dequeue(self):\r\n        if self.is_empty():\r\n            print(\"L\u1ed7i: H\u00e0ng \u0111\u1ee3i r\u1ed7ng!\")\r\n            return None\r\n        item = self.front.data\r\n        self.front = self.front.next\r\n        # N\u1ebfu front th\u00e0nh None sau khi dequeue, rear c\u0169ng ph\u1ea3i l\u00e0 None\r\n        if self.front is None:\r\n            self.rear = None\r\n        self.size -= 1\r\n        print(f\"\u0110\u00e3 l\u1ea5y {item} t\u1eeb \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i.\")\r\n        return item\r\n\r\n    def peek(self):\r\n        if self.is_empty():\r\n            print(\"L\u1ed7i: H\u00e0ng \u0111\u1ee3i r\u1ed7ng!\")\r\n            return None\r\n        return self.front.data\r\n\r\n    def get_size(self):\r\n         return self.size\r\n\r\n    def display(self):\r\n        print(\"Tr\u1ea1ng th\u00e1i h\u00e0ng \u0111\u1ee3i (t\u1eeb Front \u0111\u1ebfn Rear):\")\r\n        if self.is_empty():\r\n            print(\"R\u1ed7ng\")\r\n            return\r\n        current = self.front\r\n        while current:\r\n            print(current.data, end=\" -&gt; \")\r\n            current = current.next\r\n        print(\"None (End)\")\r\n\r\n\r\n# S\u1eed d\u1ee5ng th\u1eed\r\nq_ll = LinkedListQueue()\r\nq_ll.enqueue(\"A\")\r\nq_ll.enqueue(\"B\")\r\nq_ll.enqueue(\"C\")\r\nq_ll.display()\r\nprint(\"K\u00edch th\u01b0\u1edbc:\", q_ll.get_size())\r\nprint(\"Ph\u1ea7n t\u1eed \u0111\u1ea7u:\", q_ll.peek())\r\nq_ll.dequeue()\r\nq_ll.display()\r\nq_ll.dequeue()\r\nq_ll.dequeue()\r\nq_ll.dequeue() # B\u00e1o r\u1ed7ng\r\nq_ll.display()\r\n<\/code><\/pre>\n<h4>\u01afu \u0111i\u1ec3m v\u00e0 Nh\u01b0\u1ee3c \u0111i\u1ec3m (Linked List)<\/h4>\n<ul>\n<li><strong>\u01afu \u0111i\u1ec3m:<\/strong>\n<ul>\n<li>K\u00edch th\u01b0\u1edbc \u0111\u1ed9ng, d\u1ec5 d\u00e0ng thay \u0111\u1ed5i, kh\u00f4ng gi\u1edbi h\u1ea1n (ch\u1ec9 b\u1edfi b\u1ed9 nh\u1edb h\u1ec7 th\u1ed1ng).<\/li>\n<li>Kh\u00f4ng l\u00e3ng ph\u00ed b\u1ed9 nh\u1edb cho c\u00e1c v\u1ecb tr\u00ed kh\u00f4ng s\u1eed d\u1ee5ng.<\/li>\n<li>Thao t\u00e1c <code>enqueue<\/code> v\u00e0 <code>dequeue<\/code> lu\u00f4n l\u00e0 O(1) (n\u1ebfu qu\u1ea3n l\u00fd \u0111\u00fang con tr\u1ecf <code>front<\/code> v\u00e0 <code>rear<\/code>).<\/li>\n<\/ul>\n<\/li>\n<li><strong>Nh\u01b0\u1ee3c \u0111i\u1ec3m:<\/strong>\n<ul>\n<li>T\u1ed1n th\u00eam b\u1ed9 nh\u1edb cho c\u00e1c con tr\u1ecf (<code>next<\/code>).<\/li>\n<li>C\u00e1c n\u00fat n\u1eb1m r\u1ea3i r\u00e1c trong b\u1ed9 nh\u1edb, c\u00f3 th\u1ec3 kh\u00f4ng hi\u1ec7u qu\u1ea3 v\u1ec1 cache b\u1eb1ng m\u1ea3ng.<\/li>\n<li>Vi\u1ec7c qu\u1ea3n l\u00fd con tr\u1ecf c\u00f3 th\u1ec3 ph\u1ee9c t\u1ea1p h\u01a1n m\u1ed9t ch\u00fat.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Su-dung-cac-thu-vien-Queue-co-san-trong-ngon-ngu-lap-trinh\"><\/span>S\u1eed d\u1ee5ng c\u00e1c th\u01b0 vi\u1ec7n Queue c\u00f3 s\u1eb5n trong ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>C\u00e1ch \u0111\u01a1n gi\u1ea3n v\u00e0 th\u01b0\u1eddng \u0111\u01b0\u1ee3c khuy\u00ean d\u00f9ng nh\u1ea5t trong th\u1ef1c t\u1ebf l\u00e0 s\u1eed d\u1ee5ng c\u00e1c l\u1edbp ho\u1eb7c module Queue \u0111\u00e3 \u0111\u01b0\u1ee3c t\u00edch h\u1ee3p s\u1eb5n trong th\u01b0 vi\u1ec7n chu\u1ea9n c\u1ee7a ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh b\u1ea1n \u0111ang d\u00f9ng. C\u00e1c th\u01b0 vi\u1ec7n n\u00e0y th\u01b0\u1eddng \u0111\u00e3 \u0111\u01b0\u1ee3c t\u1ed1i \u01b0u h\u00f3a v\u00e0 ki\u1ec3m th\u1eed k\u1ef9 l\u01b0\u1ee1ng.<\/p>\n<h4>V\u00ed d\u1ee5 v\u1edbi Python (<code>queue.Queue<\/code>)<\/h4>\n<p>Python cung c\u1ea5p module <code>queue<\/code> v\u1edbi l\u1edbp <code>Queue<\/code> tri\u1ec3n khai h\u00e0ng \u0111\u1ee3i an to\u00e0n cho \u0111a lu\u1ed3ng (thread-safe). N\u00f3 th\u01b0\u1eddng \u0111\u01b0\u1ee3c d\u00f9ng trong l\u1eadp tr\u00ecnh \u0111\u1ed3ng th\u1eddi. N\u1ebfu kh\u00f4ng c\u1ea7n thread-safe, <code>collections.deque<\/code> l\u00e0 l\u1ef1a ch\u1ecdn hi\u1ec7u qu\u1ea3 h\u01a1n cho Queue th\u00f4ng th\u01b0\u1eddng.<\/p>\n<p>Python<\/p>\n<pre><code class=\"language-plaintext\">import queue\r\nimport collections\r\n\r\n# S\u1eed d\u1ee5ng queue.Queue (thread-safe)\r\nq_threadsafe = queue.Queue()\r\nq_threadsafe.put(1) # T\u01b0\u01a1ng \u0111\u01b0\u01a1ng enqueue\r\nq_threadsafe.put(2)\r\nprint(\"L\u1ea5y t\u1eeb queue.Queue:\", q_threadsafe.get()) # T\u01b0\u01a1ng \u0111\u01b0\u01a1ng dequeue\r\n\r\n# S\u1eed d\u1ee5ng collections.deque (hi\u1ec7u qu\u1ea3 h\u01a1n cho single-thread)\r\nq_deque = collections.deque()\r\nq_deque.append(10) # Enqueue v\u00e0o b\u00ean ph\u1ea3i (\u0111u\u00f4i)\r\nq_deque.append(20)\r\nprint(\"L\u1ea5y t\u1eeb collections.deque:\", q_deque.popleft()) # Dequeue t\u1eeb b\u00ean tr\u00e1i (\u0111\u1ea7u)\r\nprint(\"Ph\u1ea7n t\u1eed \u0111\u1ea7u (peek):\", q_deque[0])\r\n<\/code><\/pre>\n<h4>V\u00ed d\u1ee5 v\u1edbi Java (<code>java.util.Queue<\/code>)<\/h4>\n<p>Java cung c\u1ea5p interface <code>java.util.Queue<\/code> v\u00e0 c\u00e1c l\u1edbp tri\u1ec3n khai nh\u01b0 <code>LinkedList<\/code> ho\u1eb7c <code>ArrayDeque<\/code>. <code>LinkedList<\/code> l\u00e0 l\u1ef1a ch\u1ecdn ph\u1ed5 bi\u1ebfn v\u00ec n\u00f3 tri\u1ec3n khai c\u1ea3 <code>List<\/code> v\u00e0 <code>Queue<\/code>\/<code>Deque<\/code>.<\/p>\n<p>Java<\/p>\n<pre><code class=\"language-plaintext\">import java.util.LinkedList;\r\nimport java.util.Queue;\r\n\r\npublic class JavaQueueExample {\r\n    public static void main(String[] args) {\r\n        \/\/ S\u1eed d\u1ee5ng LinkedList nh\u01b0 m\u1ed9t Queue\r\n        Queue&lt;String&gt; fruitQueue = new LinkedList&lt;&gt;();\r\n\r\n        \/\/ Enqueue - s\u1eed d\u1ee5ng add() ho\u1eb7c offer()\r\n        fruitQueue.add(\"Apple\"); \/\/ N\u00e9m exception n\u1ebfu th\u1ea5t b\u1ea1i (v\u00ed d\u1ee5: queue \u0111\u1ea7y - \u00edt x\u1ea3y ra v\u1edbi LinkedList)\r\n        fruitQueue.offer(\"Banana\"); \/\/ Tr\u1ea3 v\u1ec1 false n\u1ebfu th\u1ea5t b\u1ea1i\r\n        fruitQueue.offer(\"Cherry\");\r\n        System.out.println(\"H\u00e0ng \u0111\u1ee3i tr\u00e1i c\u00e2y: \" + fruitQueue);\r\n\r\n        \/\/ Peek - xem ph\u1ea7n t\u1eed \u0111\u1ea7u (kh\u00f4ng x\u00f3a) - s\u1eed d\u1ee5ng element() ho\u1eb7c peek()\r\n        System.out.println(\"Ph\u1ea7n t\u1eed \u0111\u1ea7u (element): \" + fruitQueue.element()); \/\/ N\u00e9m exception n\u1ebfu r\u1ed7ng\r\n        System.out.println(\"Ph\u1ea7n t\u1eed \u0111\u1ea7u (peek): \" + fruitQueue.peek());     \/\/ Tr\u1ea3 v\u1ec1 null n\u1ebfu r\u1ed7ng\r\n\r\n        \/\/ Dequeue - l\u1ea5y v\u00e0 x\u00f3a ph\u1ea7n t\u1eed \u0111\u1ea7u - s\u1eed d\u1ee5ng remove() ho\u1eb7c poll()\r\n        String firstFruit = fruitQueue.remove(); \/\/ N\u00e9m exception n\u1ebfu r\u1ed7ng\r\n        System.out.println(\"\u0110\u00e3 l\u1ea5y (remove): \" + firstFruit);\r\n        String secondFruit = fruitQueue.poll();   \/\/ Tr\u1ea3 v\u1ec1 null n\u1ebfu r\u1ed7ng\r\n        System.out.println(\"\u0110\u00e3 l\u1ea5y (poll): \" + secondFruit);\r\n\r\n        System.out.println(\"H\u00e0ng \u0111\u1ee3i c\u00f2n l\u1ea1i: \" + fruitQueue);\r\n    }\r\n}\r\n<\/code><\/pre>\n<h4>V\u00ed d\u1ee5 v\u1edbi C++ (<code>std::queue<\/code>)<\/h4>\n<p>C++ STL cung c\u1ea5p <code>std::queue<\/code> trong header <code>&lt;queue&gt;<\/code>. N\u00f3 l\u00e0 m\u1ed9t b\u1ed9 \u0111i\u1ec1u h\u1ee3p container (container adaptor), m\u1eb7c \u0111\u1ecbnh s\u1eed d\u1ee5ng <code>std::deque<\/code> l\u00e0m container b\u00ean d\u01b0\u1edbi, nh\u01b0ng c\u00f3 th\u1ec3 thay \u0111\u1ed5i (v\u00ed d\u1ee5 <code>std::list<\/code>).<\/p>\n<p>C++<\/p>\n<pre><code class=\"language-plaintext\">#include &lt;iostream&gt;\r\n#include &lt;queue&gt;\r\n#include &lt;string&gt;\r\n\r\nint main() {\r\n    \/\/ Kh\u1edfi t\u1ea1o m\u1ed9t queue ch\u1ee9a string\r\n    std::queue&lt;std::string&gt; tasks;\r\n\r\n    \/\/ Enqueue - s\u1eed d\u1ee5ng push()\r\n    tasks.push(\"Task 1: Coding\");\r\n    tasks.push(\"Task 2: Testing\");\r\n    tasks.push(\"Task 3: Deployment\");\r\n    std::cout &lt;&lt; \"S\u1ed1 l\u01b0\u1ee3ng task hi\u1ec7n t\u1ea1i: \" &lt;&lt; tasks.size() &lt;&lt; std::endl;\r\n\r\n    \/\/ Peek - xem ph\u1ea7n t\u1eed \u0111\u1ea7u v\u00e0 cu\u1ed1i\r\n    std::cout &lt;&lt; \"Task \u0111\u1ea7u ti\u00ean (front): \" &lt;&lt; tasks.front() &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"Task cu\u1ed1i c\u00f9ng (back): \" &lt;&lt; tasks.back() &lt;&lt; std::endl; \/\/ std::queue cho ph\u00e9p xem c\u1ea3 back\r\n\r\n    \/\/ Dequeue - s\u1eed d\u1ee5ng pop()\r\n    std::cout &lt;&lt; \"\u0110ang x\u1eed l\u00fd: \" &lt;&lt; tasks.front() &lt;&lt; std::endl;\r\n    tasks.pop(); \/\/ Ch\u1ec9 x\u00f3a, kh\u00f4ng tr\u1ea3 v\u1ec1 gi\u00e1 tr\u1ecb\r\n\r\n    std::cout &lt;&lt; \"Task \u0111\u1ea7u ti\u00ean sau khi pop: \" &lt;&lt; tasks.front() &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"S\u1ed1 l\u01b0\u1ee3ng task c\u00f2n l\u1ea1i: \" &lt;&lt; tasks.size() &lt;&lt; std::endl;\r\n\r\n    \/\/ Ki\u1ec3m tra r\u1ed7ng\r\n    if (!tasks.empty()) {\r\n        std::cout &lt;&lt; \"Queue ch\u01b0a r\u1ed7ng.\" &lt;&lt; std::endl;\r\n    }\r\n\r\n    return 0;\r\n}\r\n<\/code><\/pre>\n<p>Vi\u1ec7c l\u1ef1a ch\u1ecdn c\u00e1ch tri\u1ec3n khai n\u00e0o (t\u1ef1 vi\u1ebft b\u1eb1ng m\u1ea3ng\/linked list hay d\u00f9ng th\u01b0 vi\u1ec7n) ph\u1ee5 thu\u1ed9c v\u00e0o y\u00eau c\u1ea7u c\u1ee5 th\u1ec3 c\u1ee7a b\u00e0i to\u00e1n, ng\u00f4n ng\u1eef s\u1eed d\u1ee5ng v\u00e0 c\u00e1c y\u1ebfu t\u1ed1 v\u1ec1 hi\u1ec7u n\u0103ng, s\u1ef1 ti\u1ec7n l\u1ee3i. Tuy nhi\u00ean, trong h\u1ea7u h\u1ebft tr\u01b0\u1eddng h\u1ee3p, s\u1eed d\u1ee5ng th\u01b0 vi\u1ec7n chu\u1ea9n l\u00e0 c\u00e1ch ti\u1ebfp c\u1eadn t\u1ed1t nh\u1ea5t.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Ung-dung-quan-trong-cua-Queue-trong-Lap-trinh-va-He-thong\"><\/span>\u1ee8ng d\u1ee5ng quan tr\u1ecdng c\u1ee7a Queue trong L\u1eadp tr\u00ecnh v\u00e0 H\u1ec7 th\u1ed1ng<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Nguy\u00ean t\u1eafc FIFO \u0111\u01a1n gi\u1ea3n nh\u01b0ng m\u1ea1nh m\u1ebd c\u1ee7a Queue l\u00e0m cho n\u00f3 tr\u1edf th\u00e0nh m\u1ed9t c\u00f4ng c\u1ee5 c\u1ef1c k\u1ef3 h\u1eefu \u00edch trong nhi\u1ec1u l\u0129nh v\u1ef1c c\u1ee7a khoa h\u1ecdc m\u00e1y t\u00ednh v\u00e0 k\u1ef9 thu\u1eadt ph\u1ea7n m\u1ec1m. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t s\u1ed1 \u1ee9ng d\u1ee5ng ti\u00eau bi\u1ec3u v\u00e0 quan tr\u1ecdng:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-02.jpg\" alt=\"Queue 02\" width=\"750\" height=\"497\" class=\"aligncenter size-full wp-image-27340\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-02.jpg 750w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-02-300x199.jpg 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n<h3><span class=\"ez-toc-section\" id=\"Lap-lich-tac-vu-Task-Scheduling-trong-He-dieu-hanh\"><\/span>L\u1eadp l\u1ecbch t\u00e1c v\u1ee5 (Task Scheduling) trong H\u1ec7 \u0111i\u1ec1u h\u00e0nh<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>H\u1ec7 \u0111i\u1ec1u h\u00e0nh (Operating System &#8211; OS)<\/strong> th\u01b0\u1eddng s\u1eed d\u1ee5ng Queue \u0111\u1ec3 qu\u1ea3n l\u00fd c\u00e1c ti\u1ebfn tr\u00ecnh (processes) ho\u1eb7c lu\u1ed3ng (threads) \u0111ang ch\u1edd \u0111\u01b0\u1ee3c c\u1ea5p ph\u00e1t t\u00e0i nguy\u00ean h\u1ec7 th\u1ed1ng, \u0111\u1eb7c bi\u1ec7t l\u00e0 CPU. Khi m\u1ed9t ti\u1ebfn tr\u00ecnh s\u1eb5n s\u00e0ng ch\u1ea1y nh\u01b0ng CPU \u0111ang b\u1eadn, n\u00f3 s\u1ebd \u0111\u01b0\u1ee3c \u0111\u01b0a v\u00e0o m\u1ed9t h\u00e0ng \u0111\u1ee3i (ready queue).<\/p>\n<p>B\u1ed9 l\u1eadp l\u1ecbch (scheduler) c\u1ee7a OS s\u1ebd ch\u1ecdn ti\u1ebfn tr\u00ecnh t\u1eeb \u0111\u1ea7u h\u00e0ng \u0111\u1ee3i n\u00e0y \u0111\u1ec3 c\u1ea5p ph\u00e1t CPU theo m\u1ed9t thu\u1eadt to\u00e1n n\u00e0o \u0111\u00f3 (v\u00ed d\u1ee5: First-Come, First-Served &#8211; FCFS, ch\u00ednh l\u00e0 FIFO). Queue \u0111\u1ea3m b\u1ea3o c\u00e1c ti\u1ebfn tr\u00ecnh \u0111\u01b0\u1ee3c xem x\u00e9t c\u1ea5p CPU m\u1ed9t c\u00e1ch c\u00f4ng b\u1eb1ng theo th\u1ee9 t\u1ef1 ch\u00fang s\u1eb5n s\u00e0ng. T\u01b0\u01a1ng t\u1ef1, Queue c\u0169ng d\u00f9ng \u0111\u1ec3 qu\u1ea3n l\u00fd c\u00e1c y\u00eau c\u1ea7u I\/O \u0111ang ch\u1edd thi\u1ebft b\u1ecb.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Thuat-toan-Tim-kiem-theo-chieu-rong-BFS-%E2%80%93-Breadth-First-Search\"><\/span>Thu\u1eadt to\u00e1n T\u00ecm ki\u1ebfm theo chi\u1ec1u r\u1ed9ng (BFS &#8211; Breadth-First Search)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>T\u00ecm ki\u1ebfm theo chi\u1ec1u r\u1ed9ng (BFS)<\/strong> l\u00e0 m\u1ed9t thu\u1eadt to\u00e1n duy\u1ec7t ho\u1eb7c t\u00ecm ki\u1ebfm tr\u00ean \u0111\u1ed3 th\u1ecb (graph) ho\u1eb7c c\u00e2y (tree). BFS kh\u00e1m ph\u00e1 c\u00e1c \u0111\u1ec9nh k\u1ec1 v\u1edbi \u0111\u1ec9nh xu\u1ea5t ph\u00e1t tr\u01b0\u1edbc, sau \u0111\u00f3 m\u1edbi \u0111i s\u00e2u v\u00e0o c\u00e1c \u0111\u1ec9nh xa h\u01a1n. \u0110\u1ec3 theo d\u00f5i c\u00e1c \u0111\u1ec9nh c\u1ea7n \u0111\u01b0\u1ee3c kh\u00e1m ph\u00e1, BFS s\u1eed d\u1ee5ng m\u1ed9t Queue.<\/p>\n<p>Thu\u1eadt to\u00e1n b\u1eaft \u0111\u1ea7u b\u1eb1ng c\u00e1ch \u0111\u01b0a \u0111\u1ec9nh g\u1ed1c v\u00e0o Queue. Sau \u0111\u00f3, trong khi Queue c\u00f2n ph\u1ea7n t\u1eed, n\u00f3 l\u1eb7p l\u1ea1i qu\u00e1 tr\u00ecnh: l\u1ea5y m\u1ed9t \u0111\u1ec9nh ra (<code>dequeue<\/code>), x\u1eed l\u00fd \u0111\u1ec9nh \u0111\u00f3, v\u00e0 \u0111\u01b0a t\u1ea5t c\u1ea3 c\u00e1c \u0111\u1ec9nh k\u1ec1 ch\u01b0a \u0111\u01b0\u1ee3c th\u0103m c\u1ee7a n\u00f3 v\u00e0o cu\u1ed1i Queue (<code>enqueue<\/code>). Queue \u0111\u1ea3m b\u1ea3o c\u00e1c \u0111\u1ec9nh \u0111\u01b0\u1ee3c duy\u1ec7t theo t\u1eebng m\u1ee9c, \u0111\u00fang tinh th\u1ea7n c\u1ee7a BFS.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Quan-ly-Bo-dem-Buffers-trong-xu-ly-luong-du-lieu-IO\"><\/span>Qu\u1ea3n l\u00fd B\u1ed9 \u0111\u1ec7m (Buffers) trong x\u1eed l\u00fd lu\u1ed3ng d\u1eef li\u1ec7u (I\/O)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>B\u1ed9 \u0111\u1ec7m (Buffer)<\/strong> l\u00e0 m\u1ed9t v\u00f9ng nh\u1edb t\u1ea1m th\u1eddi \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 ch\u1ee9a d\u1eef li\u1ec7u trong khi truy\u1ec1n gi\u1eefa c\u00e1c thi\u1ebft b\u1ecb ho\u1eb7c gi\u1eefa ch\u01b0\u01a1ng tr\u00ecnh v\u00e0 thi\u1ebft b\u1ecb c\u00f3 t\u1ed1c \u0111\u1ed9 kh\u00e1c nhau (v\u00ed d\u1ee5: gi\u1eefa CPU v\u00e0 \u1ed5 \u0111\u0129a, ho\u1eb7c qua m\u1ea1ng). Queue th\u01b0\u1eddng \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 tri\u1ec3n khai buffer.<\/p>\n<p>D\u1eef li\u1ec7u t\u1eeb ngu\u1ed3n nhanh h\u01a1n (v\u00ed d\u1ee5: CPU ghi d\u1eef li\u1ec7u) \u0111\u01b0\u1ee3c <code>enqueue<\/code> v\u00e0o buffer. D\u1eef li\u1ec7u s\u1ebd \u0111\u01b0\u1ee3c thi\u1ebft b\u1ecb ch\u1eadm h\u01a1n (v\u00ed d\u1ee5: \u1ed5 \u0111\u0129a \u0111\u1ecdc d\u1eef li\u1ec7u) <code>dequeue<\/code> t\u1eeb buffer khi n\u00f3 s\u1eb5n s\u00e0ng. Queue gi\u00fap l\u00e0m m\u01b0\u1ee3t s\u1ef1 ch\u00eanh l\u1ec7ch t\u1ed1c \u0111\u1ed9, tr\u00e1nh m\u1ea5t m\u00e1t d\u1eef li\u1ec7u v\u00e0 t\u0103ng hi\u1ec7u qu\u1ea3 truy\u1ec1n nh\u1eadn. V\u00ed d\u1ee5 \u0111i\u1ec3n h\u00ecnh l\u00e0 buffer b\u00e0n ph\u00edm, buffer m\u1ea1ng.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Xu-ly-yeu-cau-theo-thu-tu-Vi-du-Hang-doi-tin-nhan-%E2%80%93-Message-Queue\"><\/span>X\u1eed l\u00fd y\u00eau c\u1ea7u theo th\u1ee9 t\u1ef1 (V\u00ed d\u1ee5: H\u00e0ng \u0111\u1ee3i tin nh\u1eafn &#8211; Message Queue)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Trong c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n ho\u1eb7c \u1ee9ng d\u1ee5ng d\u1ef1a tr\u00ean s\u1ef1 ki\u1ec7n, <strong>H\u00e0ng \u0111\u1ee3i tin nh\u1eafn (Message Queue)<\/strong> \u0111\u00f3ng vai tr\u00f2 trung t\u00e2m. C\u00e1c th\u00e0nh ph\u1ea7n kh\u00e1c nhau c\u1ee7a h\u1ec7 th\u1ed1ng giao ti\u1ebfp v\u1edbi nhau b\u1eb1ng c\u00e1ch g\u1eedi v\u00e0 nh\u1eadn tin nh\u1eafn th\u00f4ng qua c\u00e1c Queue.<\/p>\n<p>M\u1ed9t th\u00e0nh ph\u1ea7n (producer) g\u1eedi tin nh\u1eafn (y\u00eau c\u1ea7u, d\u1eef li\u1ec7u, s\u1ef1 ki\u1ec7n) v\u00e0o m\u1ed9t Queue. Th\u00e0nh ph\u1ea7n kh\u00e1c (consumer) s\u1ebd l\u1ea5y tin nh\u1eafn t\u1eeb Queue \u0111\u00f3 \u0111\u1ec3 x\u1eed l\u00fd. Queue \u0111\u1ea3m b\u1ea3o c\u00e1c tin nh\u1eafn \u0111\u01b0\u1ee3c x\u1eed l\u00fd theo th\u1ee9 t\u1ef1 (FIFO), gi\u00fap t\u00e1ch r\u1eddi (decoupling) c\u00e1c th\u00e0nh ph\u1ea7n v\u00e0 t\u0103ng kh\u1ea3 n\u0103ng ch\u1ecbu l\u1ed7i, m\u1edf r\u1ed9ng c\u1ee7a h\u1ec7 th\u1ed1ng. V\u00ed d\u1ee5: RabbitMQ, Apache Kafka (d\u00f9 Kafka ph\u1ee9c t\u1ea1p h\u01a1n Queue truy\u1ec1n th\u1ed1ng).<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Mo-phong-he-thong-doi-Vi-du-Quay-dich-vu-khach-hang\"><\/span>M\u00f4 ph\u1ecfng h\u1ec7 th\u1ed1ng \u0111\u1ee3i (V\u00ed d\u1ee5: Qu\u1ea7y d\u1ecbch v\u1ee5 kh\u00e1ch h\u00e0ng)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Queue l\u00e0 c\u00f4ng c\u1ee5 l\u00fd t\u01b0\u1edfng \u0111\u1ec3 m\u00f4 ph\u1ecfng c\u00e1c h\u1ec7 th\u1ed1ng trong th\u1ebf gi\u1edbi th\u1ef1c c\u00f3 li\u00ean quan \u0111\u1ebfn vi\u1ec7c ch\u1edd \u0111\u1ee3i, v\u00ed d\u1ee5 nh\u01b0 m\u00f4 ph\u1ecfng ho\u1ea1t \u0111\u1ed9ng c\u1ee7a m\u1ed9t trung t\u00e2m d\u1ecbch v\u1ee5 kh\u00e1ch h\u00e0ng, m\u1ed9t h\u1ec7 th\u1ed1ng giao th\u00f4ng, ho\u1eb7c m\u1ed9t d\u00e2y chuy\u1ec1n s\u1ea3n xu\u1ea5t.<\/p>\n<p>B\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng Queue \u0111\u1ec3 bi\u1ec3u di\u1ec5n h\u00e0ng ch\u1edd kh\u00e1ch h\u00e0ng ho\u1eb7c c\u00f4ng vi\u1ec7c, c\u00e1c nh\u00e0 ph\u00e2n t\u00edch c\u00f3 th\u1ec3 m\u00f4 ph\u1ecfng c\u00e1c k\u1ecbch b\u1ea3n kh\u00e1c nhau, thay \u0111\u1ed5i s\u1ed1 l\u01b0\u1ee3ng nh\u00e2n vi\u00ean ph\u1ee5c v\u1ee5, t\u1ed1c \u0111\u1ed9 x\u1eed l\u00fd, v.v., \u0111\u1ec3 \u0111\u00e1nh gi\u00e1 hi\u1ec7u n\u0103ng h\u1ec7 th\u1ed1ng, th\u1eddi gian ch\u1edd trung b\u00ecnh, v\u00e0 \u0111\u01b0a ra quy\u1ebft \u0111\u1ecbnh t\u1ed1i \u01b0u h\u00f3a.<\/p>\n<p>Nh\u1eefng \u1ee9ng d\u1ee5ng n\u00e0y ch\u1ec9 l\u00e0 m\u1ed9t ph\u1ea7n nh\u1ecf cho th\u1ea5y s\u1ef1 \u0111a d\u1ea1ng v\u00e0 t\u1ea7m quan tr\u1ecdng c\u1ee7a Queue. B\u1ea5t c\u1ee9 khi n\u00e0o b\u1ea1n c\u1ea7n x\u1eed l\u00fd c\u00e1c m\u1ee5c theo th\u1ee9 t\u1ef1 ch\u00fang \u0111\u1ebfn, Queue l\u00e0 m\u1ed9t \u1ee9ng vi\u00ean s\u00e1ng gi\u00e1.<\/p>\n<div style=\"background-color: #e6f2ff; border-radius: 10px; padding: 20px; margin: 20px 0; border: 1px solid #b3d9ff;\">\n<p><strong>C\u00d3 TH\u1ec2 B\u1ea0N QUAN T\u00c2M<\/strong><\/p>\n<p>\u0110\u1ec3 c\u00e1c \u1ee9ng d\u1ee5ng web, h\u1ec7 th\u1ed1ng x\u1eed l\u00fd t\u00e1c v\u1ee5 hay game server c\u1ee7a b\u1ea1n v\u1eadn h\u00e0nh \u1ed5n \u0111\u1ecbnh, vi\u1ec7c l\u1ef1a ch\u1ecdn n\u1ec1n t\u1ea3ng h\u1ea1 t\u1ea7ng ph\u00f9 h\u1ee3p l\u00e0 r\u1ea5t quan tr\u1ecdng. B\u1ea1n c\u00f3 th\u1ec3 b\u1eaft \u0111\u1ea7u v\u1edbi <a href=\"https:\/\/interdata.vn\/thue-hosting\/\">d\u1ecbch v\u1ee5 Web Hosting gi\u00e1 r\u1ebb ch\u1ea5t l\u01b0\u1ee3ng cao ch\u1ec9 t\u1eeb 1K\/Ng\u00e0y<\/a>\u00a0t\u1ea1i InterData. Khi c\u1ea7n nhi\u1ec1u t\u00e0i nguy\u00ean v\u00e0 kh\u1ea3 n\u0103ng ki\u1ec3m so\u00e1t cao h\u01a1n, h\u00e3y tham kh\u1ea3o <a target=\"_blank\" href=\"https:\/\/interdata.vn\/thue-vps\/\" rel=\"noopener\">d\u1ecbch v\u1ee5 VPS Hosting gi\u00e1 r\u1ebb (3K\/Ng\u00e0y) uy t\u00edn t\u1ed1c \u0111\u1ed9 cao<\/a> v\u1edbi ph\u1ea7n c\u1ee9ng chuy\u00ean d\u1ee5ng m\u1ea1nh m\u1ebd.<\/p>\n<p>\u0110\u1ed1i v\u1edbi c\u00e1c d\u1ef1 \u00e1n \u0111\u00f2i h\u1ecfi c\u1ea5u h\u00ecnh cao v\u00e0 s\u1ef1 linh ho\u1ea1t t\u1ed1i \u0111a, <a target=\"_blank\" href=\"https:\/\/interdata.vn\/cloud-server\/\" rel=\"noopener\">d\u1ecbch v\u1ee5 Cloud Server ch\u1ea5t l\u01b0\u1ee3ng gi\u00e1 r\u1ebb (5K\/Ng\u00e0y) c\u1ea5u h\u00ecnh cao<\/a> l\u00e0 gi\u1ea3i ph\u00e1p l\u00fd t\u01b0\u1edfng. InterData trang b\u1ecb ph\u1ea7n c\u1ee9ng th\u1ebf h\u1ec7 m\u1edbi nh\u01b0 chip AMD EPYC Gen 3, \u1ed5 c\u1ee9ng SSD NVMe U.2, k\u1ebft h\u1ee3p c\u00f4ng ngh\u1ec7 \u1ea3o h\u00f3a ti\u00ean ti\u1ebfn v\u00e0 b\u0103ng th\u00f4ng cao, mang \u0111\u1ebfn t\u1ed1c \u0111\u1ed9 v\u01b0\u1ee3t tr\u1ed9i v\u00e0 s\u1ef1 \u1ed5n \u0111\u1ecbnh.<\/p>\n<\/div>\n<h2><span class=\"ez-toc-section\" id=\"So-sanh-chi-tiet-giua-Queue-va-Stack\"><\/span>So s\u00e1nh chi ti\u1ebft gi\u1eefa Queue v\u00e0 Stack<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Queue v\u00e0 <strong>Stack (Ng\u0103n x\u1ebfp)<\/strong> \u0111\u1ec1u l\u00e0 c\u00e1c c\u1ea5u tr\u00fac d\u1eef li\u1ec7u tuy\u1ebfn t\u00ednh c\u01a1 b\u1ea3n, d\u00f9ng \u0111\u1ec3 l\u01b0u tr\u1eef m\u1ed9t d\u00e3y c\u00e1c ph\u1ea7n t\u1eed. Tuy nhi\u00ean, ch\u00fang kh\u00e1c bi\u1ec7t ho\u00e0n to\u00e0n v\u1ec1 nguy\u00ean t\u1eafc ho\u1ea1t \u0111\u1ed9ng v\u00e0 c\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng \u0111i\u1ec3n h\u00ecnh. Hi\u1ec3u r\u00f5 s\u1ef1 kh\u00e1c bi\u1ec7t n\u00e0y l\u00e0 r\u1ea5t quan tr\u1ecdng.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Diem-giong-nhau-co-ban\"><\/span>\u0110i\u1ec3m gi\u1ed1ng nhau c\u01a1 b\u1ea3n<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li><strong>C\u1ea5u tr\u00fac tuy\u1ebfn t\u00ednh:<\/strong> C\u1ea3 hai \u0111\u1ec1u l\u01b0u tr\u1eef d\u1eef li\u1ec7u d\u01b0\u1edbi d\u1ea1ng m\u1ed9t chu\u1ed7i tu\u1ea7n t\u1ef1.<\/li>\n<li><strong>Ki\u1ec3u d\u1eef li\u1ec7u tr\u1eebu t\u01b0\u1ee3ng (ADT):<\/strong> C\u1ea3 hai \u0111\u1ec1u \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a b\u1edfi c\u00e1c thao t\u00e1c m\u00e0 ch\u00fang h\u1ed7 tr\u1ee3, kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1ch tri\u1ec3n khai c\u1ee5 th\u1ec3.<\/li>\n<li><strong>Thao t\u00e1c th\u00eam\/x\u00f3a:<\/strong> C\u1ea3 hai \u0111\u1ec1u c\u00f3 thao t\u00e1c c\u01a1 b\u1ea3n \u0111\u1ec3 th\u00eam v\u00e0 x\u00f3a ph\u1ea7n t\u1eed.<\/li>\n<li><strong>Tri\u1ec3n khai:<\/strong> C\u1ea3 hai \u0111\u1ec1u c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c tri\u1ec3n khai b\u1eb1ng M\u1ea3ng ho\u1eb7c Danh s\u00e1ch li\u00ean k\u1ebft.<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Khac-biet-cot-loi-Nguyen-tac-FIFO-vs-LIFO\"><\/span>Kh\u00e1c bi\u1ec7t c\u1ed1t l\u00f5i: Nguy\u00ean t\u1eafc FIFO vs LIFO<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u0110\u00e2y l\u00e0 \u0111i\u1ec3m kh\u00e1c bi\u1ec7t c\u0103n b\u1ea3n nh\u1ea5t v\u00e0 \u0111\u1ecbnh h\u00ecnh m\u1ecdi th\u1ee9 kh\u00e1c:<\/p>\n<ul>\n<li><strong>Queue:<\/strong> Ho\u1ea1t \u0111\u1ed9ng theo nguy\u00ean t\u1eafc <strong>FIFO (First-In, First-Out)<\/strong>. Ph\u1ea7n t\u1eed \u0111\u01b0\u1ee3c th\u00eam v\u00e0o \u0111\u1ea7u ti\u00ean s\u1ebd \u0111\u01b0\u1ee3c l\u1ea5y ra \u0111\u1ea7u ti\u00ean. Gi\u1ed1ng nh\u01b0 h\u00e0ng \u0111\u1ee3i.\n<ul>\n<li>Th\u00eam v\u00e0o cu\u1ed1i (Rear\/Tail) &#8211; <code>Enqueue<\/code>.<\/li>\n<li>X\u00f3a t\u1eeb \u0111\u1ea7u (Front\/Head) &#8211; <code>Dequeue<\/code>.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Stack:<\/strong> Ho\u1ea1t \u0111\u1ed9ng theo nguy\u00ean t\u1eafc <strong>LIFO (Last-In, First-Out)<\/strong> ho\u1eb7c <strong>FILO (First-In, Last-Out)<\/strong>. Ph\u1ea7n t\u1eed \u0111\u01b0\u1ee3c th\u00eam v\u00e0o sau c\u00f9ng s\u1ebd \u0111\u01b0\u1ee3c l\u1ea5y ra \u0111\u1ea7u ti\u00ean. Gi\u1ed1ng nh\u01b0 ch\u1ed3ng \u0111\u0129a.\n<ul>\n<li>Th\u00eam v\u00e0o \u0111\u1ec9nh (Top) &#8211; <code>Push<\/code>.<\/li>\n<li>X\u00f3a t\u1eeb \u0111\u1ec9nh (Top) &#8211; <code>Pop<\/code>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>S\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 c\u01a1 ch\u1ebf truy c\u1eadp n\u00e0y d\u1eabn \u0111\u1ebfn vi\u1ec7c ch\u00fang ph\u00f9 h\u1ee3p cho c\u00e1c lo\u1ea1i b\u00e0i to\u00e1n ho\u00e0n to\u00e0n kh\u00e1c nhau.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Truong-hop-su-dung-dien-hinh-cua-tung-loai\"><\/span>Tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng \u0111i\u1ec3n h\u00ecnh c\u1ee7a t\u1eebng lo\u1ea1i<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li><strong>Queue (FIFO &#8211; Th\u1ee9 t\u1ef1, C\u00f4ng b\u1eb1ng):<\/strong>\n<ul>\n<li>Qu\u1ea3n l\u00fd t\u00e0i nguy\u00ean chia s\u1ebb (l\u1eadp l\u1ecbch CPU, h\u00e0ng \u0111\u1ee3i in).<\/li>\n<li>X\u1eed l\u00fd d\u1eef li\u1ec7u theo th\u1ee9 t\u1ef1 \u0111\u1ebfn (buffer I\/O, message queue).<\/li>\n<li>Thu\u1eadt to\u00e1n duy\u1ec7t \u0111\u1ed3 th\u1ecb\/c\u00e2y theo m\u1ee9c (BFS).<\/li>\n<li>M\u00f4 ph\u1ecfng h\u1ec7 th\u1ed1ng h\u00e0ng \u0111\u1ee3i.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Stack (LIFO &#8211; Ho\u00e0n t\u00e1c, \u0110\u1ec7 quy):<\/strong>\n<ul>\n<li>Qu\u1ea3n l\u00fd l\u1eddi g\u1ecdi h\u00e0m (Call Stack trong th\u1ef1c thi ch\u01b0\u01a1ng tr\u00ecnh).<\/li>\n<li>Ch\u1ee9c n\u0103ng Ho\u00e0n t\u00e1c\/L\u00e0m l\u1ea1i (Undo\/Redo) trong \u1ee9ng d\u1ee5ng.<\/li>\n<li>Ki\u1ec3m tra d\u1ea5u ngo\u1eb7c h\u1ee3p l\u1ec7.<\/li>\n<li>\u0110\u00e1nh gi\u00e1 bi\u1ec3u th\u1ee9c (postfix, infix).<\/li>\n<li>Thu\u1eadt to\u00e1n duy\u1ec7t \u0111\u1ed3 th\u1ecb\/c\u00e2y theo chi\u1ec1u s\u00e2u (DFS &#8211; Depth-First Search, th\u01b0\u1eddng d\u00f9ng \u0111\u1ec7 quy &#8211; \u1ea9n ch\u1ee9a Stack).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>B\u1ea3ng so s\u00e1nh nhanh:<\/strong><\/p>\n<figure class=\"table\">\n<table>\n<thead>\n<tr>\n<th>\u0110\u1eb7c \u0111i\u1ec3m<\/th>\n<th>Queue (H\u00e0ng \u0111\u1ee3i)<\/th>\n<th>Stack (Ng\u0103n x\u1ebfp)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Nguy\u00ean t\u1eafc<\/strong><\/td>\n<td>FIFO (First-In, First-Out)<\/td>\n<td>LIFO (Last-In, First-Out)<\/td>\n<\/tr>\n<tr>\n<td><strong>Th\u00eam ph\u1ea7n t\u1eed<\/strong><\/td>\n<td><code>Enqueue<\/code> (v\u00e0o cu\u1ed1i &#8211; Rear\/Tail)<\/td>\n<td><code>Push<\/code> (l\u00ean \u0111\u1ec9nh &#8211; Top)<\/td>\n<\/tr>\n<tr>\n<td><strong>X\u00f3a ph\u1ea7n t\u1eed<\/strong><\/td>\n<td><code>Dequeue<\/code> (t\u1eeb \u0111\u1ea7u &#8211; Front\/Head)<\/td>\n<td><code>Pop<\/code> (t\u1eeb \u0111\u1ec9nh &#8211; Top)<\/td>\n<\/tr>\n<tr>\n<td><strong>Xem ph\u1ea7n t\u1eed<\/strong><\/td>\n<td><code>Peek<\/code>\/<code>Front<\/code> (ph\u1ea7n t\u1eed \u0111\u1ea7u)<\/td>\n<td><code>Peek<\/code>\/<code>Top<\/code> (ph\u1ea7n t\u1eed \u0111\u1ec9nh)<\/td>\n<\/tr>\n<tr>\n<td><strong>C\u1ea5u tr\u00fac<\/strong><\/td>\n<td>C\u00f3 2 \u0111\u1ea7u truy c\u1eadp (Front &amp; Rear)<\/td>\n<td>Ch\u1ec9 c\u00f3 1 \u0111\u1ea7u truy c\u1eadp (Top)<\/td>\n<\/tr>\n<tr>\n<td><strong>V\u00ed d\u1ee5 \u0111\u1eddi th\u1ef1c<\/strong><\/td>\n<td>H\u00e0ng ng\u01b0\u1eddi ch\u1edd, h\u00e0ng \u0111\u1ee3i in<\/td>\n<td>Ch\u1ed3ng \u0111\u0129a, n\u00fat Back tr\u00ecnh duy\u1ec7t<\/td>\n<\/tr>\n<tr>\n<td><strong>\u1ee8ng d\u1ee5ng ch\u00ednh<\/strong><\/td>\n<td>L\u1eadp l\u1ecbch, BFS, Buffer, Message Queue<\/td>\n<td>G\u1ecdi h\u00e0m, Undo\/Redo, Bi\u1ec3u th\u1ee9c, DFS<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n<p>Vi\u1ec7c l\u1ef1a ch\u1ecdn gi\u1eefa Queue v\u00e0 Stack ph\u1ee5 thu\u1ed9c ho\u00e0n to\u00e0n v\u00e0o y\u00eau c\u1ea7u c\u1ee7a b\u00e0i to\u00e1n: b\u1ea1n c\u1ea7n x\u1eed l\u00fd theo th\u1ee9 t\u1ef1 \u0111\u1ebfn (Queue) hay c\u1ea7n truy c\u1eadp ph\u1ea7n t\u1eed m\u1edbi nh\u1ea5t (Stack)?<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cac-bien-the-cua-Queue\"><\/span>C\u00e1c bi\u1ebfn th\u1ec3 c\u1ee7a Queue<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Ngo\u00e0i Queue ti\u00eau chu\u1ea9n ho\u1ea1t \u0111\u1ed9ng theo nguy\u00ean t\u1eafc FIFO, c\u00f3 m\u1ed9t s\u1ed1 bi\u1ebfn th\u1ec3 ph\u1ed5 bi\u1ebfn kh\u00e1c \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 gi\u1ea3i quy\u1ebft c\u00e1c nhu c\u1ea7u c\u1ee5 th\u1ec3 h\u01a1n. Hi\u1ec3u v\u1ec1 ch\u00fang gi\u00fap b\u1ea1n c\u00f3 th\u00eam c\u00f4ng c\u1ee5 m\u1ea1nh m\u1ebd trong h\u1ed9p d\u1ee5ng c\u1ee5 l\u1eadp tr\u00ecnh c\u1ee7a m\u00ecnh.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-03.jpg\" alt=\"Queue 03\" width=\"750\" height=\"375\" class=\"aligncenter size-full wp-image-27341\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-03.jpg 750w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-03-300x150.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/04\/Queue-03-360x180.jpg 360w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n<h3><span class=\"ez-toc-section\" id=\"Hang-doi-uu-tien-Priority-Queue-Phan-tu-quan-trong-ra-truoc\"><\/span>H\u00e0ng \u0111\u1ee3i \u01b0u ti\u00ean (Priority Queue): Ph\u1ea7n t\u1eed quan tr\u1ecdng ra tr\u01b0\u1edbc<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>H\u00e0ng \u0111\u1ee3i \u01b0u ti\u00ean (Priority Queue)<\/strong> l\u00e0 m\u1ed9t bi\u1ebfn th\u1ec3 \u0111\u1eb7c bi\u1ec7t c\u1ee7a Queue. Thay v\u00ec tu\u00e2n th\u1ee7 nghi\u00eam ng\u1eb7t FIFO, n\u00f3 cho ph\u00e9p m\u1ed7i ph\u1ea7n t\u1eed c\u00f3 m\u1ed9t <strong>m\u1ee9c \u0111\u1ed9 \u01b0u ti\u00ean (priority)<\/strong> \u0111i k\u00e8m. Khi th\u1ef1c hi\u1ec7n thao t\u00e1c l\u1ea5y ph\u1ea7n t\u1eed ra (<code>dequeue<\/code> ho\u1eb7c t\u01b0\u01a1ng \u0111\u01b0\u01a1ng), ph\u1ea7n t\u1eed c\u00f3 <strong>m\u1ee9c \u0111\u1ed9 \u01b0u ti\u00ean cao nh\u1ea5t<\/strong> s\u1ebd \u0111\u01b0\u1ee3c l\u1ea5y ra tr\u01b0\u1edbc, b\u1ea5t k\u1ec3 th\u1ee9 t\u1ef1 ch\u00fang \u0111\u01b0\u1ee3c th\u00eam v\u00e0o.<\/p>\n<p>N\u1ebfu c\u00f3 nhi\u1ec1u ph\u1ea7n t\u1eed c\u00f9ng m\u1ee9c \u01b0u ti\u00ean cao nh\u1ea5t, th\u1ee9 t\u1ef1 l\u1ea5y ra gi\u1eefa ch\u00fang c\u00f3 th\u1ec3 tu\u00e2n theo FIFO ho\u1eb7c kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a r\u00f5 (t\u00f9y thu\u1ed9c v\u00e0o c\u00e1ch tri\u1ec3n khai). Priority Queue th\u01b0\u1eddng \u0111\u01b0\u1ee3c tri\u1ec3n khai hi\u1ec7u qu\u1ea3 b\u1eb1ng c\u1ea5u tr\u00fac d\u1eef li\u1ec7u <strong>Heap<\/strong>.<\/p>\n<p><strong>\u1ee8ng d\u1ee5ng:<\/strong> Thu\u1eadt to\u00e1n Dijkstra, Prim (t\u00ecm \u0111\u01b0\u1eddng \u0111i ng\u1eafn nh\u1ea5t, c\u00e2y khung nh\u1ecf nh\u1ea5t), l\u1eadp l\u1ecbch t\u00e1c v\u1ee5 d\u1ef1a tr\u00ean \u0111\u1ed9 \u01b0u ti\u00ean, qu\u1ea3n l\u00fd s\u1ef1 ki\u1ec7n trong m\u00f4 ph\u1ecfng.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Hang-doi-vong-Circular-Queue-Toi-uu-hoa-su-dung-bo-nho-mang\"><\/span>H\u00e0ng \u0111\u1ee3i v\u00f2ng (Circular Queue): T\u1ed1i \u01b0u h\u00f3a s\u1eed d\u1ee5ng b\u1ed9 nh\u1edb (m\u1ea3ng)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Nh\u01b0 \u0111\u00e3 \u0111\u1ec1 c\u1eadp \u1edf ph\u1ea7n tri\u1ec3n khai b\u1eb1ng m\u1ea3ng, <strong>H\u00e0ng \u0111\u1ee3i v\u00f2ng (Circular Queue)<\/strong> l\u00e0 m\u1ed9t k\u1ef9 thu\u1eadt t\u1ed1i \u01b0u h\u00f3a vi\u1ec7c s\u1eed d\u1ee5ng m\u1ea3ng c\u1ed1 \u0111\u1ecbnh \u0111\u1ec3 tri\u1ec3n khai Queue. N\u00f3 coi m\u1ea3ng nh\u01b0 m\u1ed9t v\u00f2ng tr\u00f2n, cho ph\u00e9p ch\u1ec9 s\u1ed1 <code>rear<\/code> v\u00e0 <code>front<\/code> &#8220;quay v\u00f2ng&#8221; v\u1ec1 \u0111\u1ea7u m\u1ea3ng khi ch\u00fang \u0111\u1ea1t \u0111\u1ebfn cu\u1ed1i.<\/p>\n<p>\u0110i\u1ec1u n\u00e0y gi\u00fap t\u1eadn d\u1ee5ng l\u1ea1i c\u00e1c v\u1ecb tr\u00ed tr\u1ed1ng \u1edf \u0111\u1ea7u m\u1ea3ng m\u00e0 <code>front<\/code> \u0111\u00e3 \u0111i qua, tr\u00e1nh t\u00ecnh tr\u1ea1ng &#8220;\u0111\u1ea7y gi\u1ea3&#8221; (Queue b\u00e1o \u0111\u1ea7y d\u00f9 m\u1ea3ng c\u00f2n ch\u1ed7 tr\u1ed1ng nh\u01b0ng \u1edf ph\u00eda tr\u01b0\u1edbc <code>front<\/code>). Circular Queue gi\u00fap s\u1eed d\u1ee5ng b\u1ed9 nh\u1edb hi\u1ec7u qu\u1ea3 h\u01a1n khi d\u00f9ng m\u1ea3ng c\u1ed1 \u0111\u1ecbnh.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Deque-Double-Ended-Queue-Themxoa-o-ca-hai-dau\"><\/span>Deque (Double-Ended Queue): Th\u00eam\/x\u00f3a \u1edf c\u1ea3 hai \u0111\u1ea7u<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Deque<\/strong> (ph\u00e1t \u00e2m l\u00e0 &#8220;deck&#8221;, vi\u1ebft t\u1eaft c\u1ee7a Double-Ended Queue) l\u00e0 m\u1ed9t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u t\u1ed5ng qu\u00e1t h\u01a1n c\u1ea3 Queue v\u00e0 Stack. N\u00f3 cho ph\u00e9p th\u00eam (<code>enqueue<\/code>) v\u00e0 x\u00f3a (<code>dequeue<\/code>) ph\u1ea7n t\u1eed \u1edf <strong>c\u1ea3 hai \u0111\u1ea7u<\/strong> (Front v\u00e0 Rear).<\/p>\n<p>V\u00ec c\u00f3 th\u1ec3 th\u00eam\/x\u00f3a \u1edf c\u1ea3 hai \u0111\u1ea7u, Deque c\u00f3 th\u1ec3 ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t Queue (th\u00eam \u1edf Rear, x\u00f3a \u1edf Front) ho\u1eb7c nh\u01b0 m\u1ed9t Stack (th\u00eam \u1edf m\u1ed9t \u0111\u1ea7u, x\u00f3a c\u0169ng \u1edf \u0111\u1ea7u \u0111\u00f3 &#8211; v\u00ed d\u1ee5 c\u00f9ng l\u00e0 Rear ho\u1eb7c c\u00f9ng l\u00e0 Front). N\u00f3 linh ho\u1ea1t h\u01a1n nh\u01b0ng c\u0169ng c\u00f3 th\u1ec3 ph\u1ee9c t\u1ea1p h\u01a1n trong m\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p.<\/p>\n<p><strong>\u1ee8ng d\u1ee5ng:<\/strong> Tri\u1ec3n khai thu\u1eadt to\u00e1n c\u1eeda s\u1ed5 tr\u01b0\u1ee3t (sliding window), qu\u1ea3n l\u00fd l\u1ecbch s\u1eed duy\u1ec7t web (th\u00eam v\u00e0o m\u1ed9t \u0111\u1ea7u, c\u00f3 th\u1ec3 x\u00f3a t\u1eeb c\u1ea3 hai \u0111\u1ea7u), l\u00e0m c\u1ea5u tr\u00fac c\u01a1 s\u1edf cho c\u00e1c thu\u1eadt to\u00e1n kh\u00e1c. Python c\u00f3 <code>collections.deque<\/code> l\u00e0 m\u1ed9t v\u00ed d\u1ee5 \u0111i\u1ec3n h\u00ecnh.<\/p>\n<p>Vi\u1ec7c hi\u1ec3u c\u00e1c bi\u1ebfn th\u1ec3 n\u00e0y m\u1edf r\u1ed9ng kh\u1ea3 n\u0103ng \u1ee9ng d\u1ee5ng c\u1ee7a kh\u00e1i ni\u1ec7m h\u00e0ng \u0111\u1ee3i v\u00e0o nhi\u1ec1u b\u00e0i to\u00e1n ph\u1ee9c t\u1ea1p h\u01a1n.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cau-hoi-thuong-gap-ve-Queue-FAQ\"><\/span>C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p v\u1ec1 Queue (FAQ)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t s\u1ed1 c\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p v\u1ec1 Queue v\u00e0 c\u00e2u tr\u1ea3 l\u1eddi ng\u1eafn g\u1ecdn, gi\u00fap b\u1ea1n c\u1ee7ng c\u1ed1 ki\u1ebfn th\u1ee9c:<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Do-phuc-tap-thoi-gian-cua-Enqueue-Dequeue-Peek-la-bao-nhieu\"><\/span>\u0110\u1ed9 ph\u1ee9c t\u1ea1p th\u1eddi gian c\u1ee7a Enqueue, Dequeue, Peek l\u00e0 bao nhi\u00eau?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Trong c\u00e1c c\u00e1ch tri\u1ec3n khai hi\u1ec7u qu\u1ea3 nh\u1ea5t (s\u1eed d\u1ee5ng Danh s\u00e1ch li\u00ean k\u1ebft ho\u1eb7c M\u1ea3ng \u0111\u1ed9ng\/M\u1ea3ng v\u00f2ng \u0111\u01b0\u1ee3c qu\u1ea3n l\u00fd t\u1ed1t), \u0111\u1ed9 ph\u1ee9c t\u1ea1p th\u1eddi gian trung b\u00ecnh v\u00e0 trong tr\u01b0\u1eddng h\u1ee3p t\u1ed1t nh\u1ea5t (best\/average case) c\u1ee7a c\u00e1c thao t\u00e1c c\u01a1 b\u1ea3n l\u00e0:<\/p>\n<ul>\n<li><strong>Enqueue:<\/strong> O(1)<\/li>\n<li><strong>Dequeue:<\/strong> O(1)<\/li>\n<li><strong>Peek \/ Front:<\/strong> O(1)<\/li>\n<li><strong>isEmpty \/ isFull \/ size (n\u1ebfu c\u00f3 bi\u1ebfn \u0111\u1ebfm):<\/strong> O(1)<\/li>\n<\/ul>\n<p>L\u01b0u \u00fd: N\u1ebfu tri\u1ec3n khai Queue b\u1eb1ng m\u1ea3ng t\u0129nh kh\u00f4ng v\u00f2ng v\u00e0 kh\u00f4ng t\u1ed1i \u01b0u, <code>enqueue<\/code> c\u00f3 th\u1ec3 m\u1ea5t O(n) n\u1ebfu c\u1ea7n d\u1ecbch chuy\u1ec3n ph\u1ea7n t\u1eed khi \u0111\u1ea7y, ho\u1eb7c <code>dequeue<\/code> c\u00f3 th\u1ec3 m\u1ea5t O(n) n\u1ebfu c\u1ea7n d\u1ecbch chuy\u1ec3n c\u00e1c ph\u1ea7n t\u1eed c\u00f2n l\u1ea1i v\u1ec1 \u0111\u1ea7u. Tuy nhi\u00ean, \u0111\u00e2y kh\u00f4ng ph\u1ea3i l\u00e0 c\u00e1ch tri\u1ec3n khai Queue hi\u1ec7u qu\u1ea3. V\u1edbi m\u1ea3ng \u0111\u1ed9ng, vi\u1ec7c thay \u0111\u1ed5i k\u00edch th\u01b0\u1edbc c\u0169ng c\u00f3 th\u1ec3 t\u1ed1n O(n) trong tr\u01b0\u1eddng h\u1ee3p x\u1ea5u nh\u1ea5t (amortized O(1)).<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Khi-nao-thi-nen-chon-dung-Queue-thay-vi-Stack-hoac-cau-truc-du-lieu-khac\"><\/span>Khi n\u00e0o th\u00ec n\u00ean ch\u1ecdn d\u00f9ng Queue thay v\u00ec Stack ho\u1eb7c c\u1ea5u tr\u00fac d\u1eef li\u1ec7u kh\u00e1c?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>B\u1ea1n n\u00ean ch\u1ecdn Queue khi b\u00e0i to\u00e1n y\u00eau c\u1ea7u x\u1eed l\u00fd c\u00e1c ph\u1ea7n t\u1eed <strong>theo \u0111\u00fang th\u1ee9 t\u1ef1 ch\u00fang \u0111\u1ebfn (FIFO)<\/strong>. H\u00e3y t\u1ef1 h\u1ecfi: &#8220;Th\u1ee9 t\u1ef1 x\u1eed l\u00fd c\u00f3 quan tr\u1ecdng kh\u00f4ng? Ph\u1ea7n t\u1eed \u0111\u1ebfn tr\u01b0\u1edbc c\u00f3 c\u1ea7n \u0111\u01b0\u1ee3c ph\u1ee5c v\u1ee5 tr\u01b0\u1edbc kh\u00f4ng?&#8221;. N\u1ebfu c\u00e2u tr\u1ea3 l\u1eddi l\u00e0 c\u00f3, Queue l\u00e0 l\u1ef1a ch\u1ecdn ph\u00f9 h\u1ee3p.<\/p>\n<p>C\u00e1c d\u1ea5u hi\u1ec7u kh\u00e1c cho th\u1ea5y n\u00ean d\u00f9ng Queue:<\/p>\n<ul>\n<li>C\u1ea7n m\u00f4 ph\u1ecfng h\u00e0ng \u0111\u1ee3i th\u1ef1c t\u1ebf.<\/li>\n<li>Tri\u1ec3n khai thu\u1eadt to\u00e1n BFS.<\/li>\n<li>C\u1ea7n buffer d\u1eef li\u1ec7u gi\u1eefa hai ti\u1ebfn tr\u00ecnh\/thi\u1ebft b\u1ecb t\u1ed1c \u0111\u1ed9 kh\u00e1c nhau.<\/li>\n<li>Qu\u1ea3n l\u00fd t\u00e0i nguy\u00ean chia s\u1ebb m\u1ed9t c\u00e1ch c\u00f4ng b\u1eb1ng.<\/li>\n<\/ul>\n<p>Ng\u01b0\u1ee3c l\u1ea1i, n\u1ebfu b\u1ea1n c\u1ea7n truy c\u1eadp ph\u1ea7n t\u1eed m\u1edbi nh\u1ea5t, x\u1eed l\u00fd theo ki\u1ec3u &#8220;ho\u00e0n t\u00e1c&#8221; ho\u1eb7c li\u00ean quan \u0111\u1ebfn \u0111\u1ec7 quy, h\u00e3y ngh\u0129 \u0111\u1ebfn Stack (LIFO). N\u1ebfu c\u1ea7n truy c\u1eadp\/t\u00ecm ki\u1ebfm\/s\u1eafp x\u1ebfp ph\u1ea7n t\u1eed b\u1ea5t k\u1ef3 nhanh ch\u00f3ng, c\u00e1c c\u1ea5u tr\u00fac kh\u00e1c nh\u01b0 M\u1ea3ng, Danh s\u00e1ch, C\u00e2y t\u00ecm ki\u1ebfm, B\u1ea3ng b\u0103m c\u00f3 th\u1ec3 ph\u00f9 h\u1ee3p h\u01a1n.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Queue-co-bi-gioi-han-kich-thuoc-toi-da-khong\"><\/span>Queue c\u00f3 b\u1ecb gi\u1edbi h\u1ea1n k\u00edch th\u01b0\u1edbc t\u1ed1i \u0111a kh\u00f4ng?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u0110i\u1ec1u n\u00e0y ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1ch tri\u1ec3n khai:<\/p>\n<ul>\n<li><strong>Tri\u1ec3n khai b\u1eb1ng M\u1ea3ng t\u0129nh (Fixed-size Array):<\/strong> C\u00f3 gi\u1edbi h\u1ea1n k\u00edch th\u01b0\u1edbc t\u1ed1i \u0111a, \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh tr\u01b0\u1edbc khi t\u1ea1o Queue. C\u1ea7n x\u1eed l\u00fd tr\u01b0\u1eddng h\u1ee3p Queue \u0111\u1ea7y (<code>isFull<\/code>).<\/li>\n<li><strong>Tri\u1ec3n khai b\u1eb1ng Danh s\u00e1ch li\u00ean k\u1ebft (Linked List) ho\u1eb7c M\u1ea3ng \u0111\u1ed9ng (Dynamic Array):<\/strong> V\u1ec1 l\u00fd thuy\u1ebft, kh\u00f4ng c\u00f3 gi\u1edbi h\u1ea1n k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh. Queue c\u00f3 th\u1ec3 ph\u00e1t tri\u1ec3n l\u1edbn t\u00f9y thu\u1ed9c v\u00e0o b\u1ed9 nh\u1edb h\u1ec7 th\u1ed1ng kh\u1ea3 d\u1ee5ng. Tuy nhi\u00ean, v\u1eabn c\u00f3 gi\u1edbi h\u1ea1n v\u1eadt l\u00fd c\u1ee7a b\u1ed9 nh\u1edb.<\/li>\n<\/ul>\n<p>Khi s\u1eed d\u1ee5ng th\u01b0 vi\u1ec7n chu\u1ea9n, h\u00e3y ki\u1ec3m tra t\u00e0i li\u1ec7u \u0111\u1ec3 bi\u1ebft li\u1ec7u tri\u1ec3n khai c\u1ee5 th\u1ec3 \u0111\u00f3 c\u00f3 gi\u1edbi h\u1ea1n k\u00edch th\u01b0\u1edbc hay kh\u00f4ng (v\u00ed d\u1ee5: <code>queue.Queue<\/code> trong Python c\u00f3 th\u1ec3 kh\u1edfi t\u1ea1o v\u1edbi <code>maxsize<\/code>).<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Khi-nao-ban-can-den-Queue\"><\/span>Khi n\u00e0o b\u1ea1n c\u1ea7n \u0111\u1ebfn Queue?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Qua b\u00e0i vi\u1ebft chi ti\u1ebft n\u00e0y, hy v\u1ecdng b\u1ea1n \u0111\u00e3 c\u00f3 c\u00e1i nh\u00ecn to\u00e0n di\u1ec7n v\u1ec1 <strong>Queue l\u00e0 g\u00ec<\/strong>. T\u1eeb \u0111\u1ecbnh ngh\u0129a c\u1ed1t l\u00f5i d\u1ef1a tr\u00ean nguy\u00ean t\u1eafc <strong>FIFO<\/strong> c\u00f4ng b\u1eb1ng, c\u00e1c thao t\u00e1c c\u01a1 b\u1ea3n nh\u01b0 <code>Enqueue<\/code>, <code>Dequeue<\/code>, <code>Peek<\/code>, \u0111\u1ebfn c\u00e1c c\u00e1ch tri\u1ec3n khai b\u1eb1ng M\u1ea3ng, Danh s\u00e1ch li\u00ean k\u1ebft v\u00e0 vi\u1ec7c s\u1eed d\u1ee5ng th\u01b0 vi\u1ec7n ti\u1ec7n l\u1ee3i.<\/p>\n<p>Ch\u00fang ta c\u0169ng \u0111\u00e3 kh\u00e1m ph\u00e1 v\u00f4 s\u1ed1 \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf quan tr\u1ecdng c\u1ee7a Queue, t\u1eeb l\u1eadp l\u1ecbch h\u1ec7 \u0111i\u1ec1u h\u00e0nh, thu\u1eadt to\u00e1n BFS, qu\u1ea3n l\u00fd buffer, h\u1ec7 th\u1ed1ng tin nh\u1eafn, cho \u0111\u1ebfn vi\u1ec7c so s\u00e1nh n\u00f3 v\u1edbi &#8220;ng\u01b0\u1eddi anh em&#8221; Stack v\u00e0 t\u00ecm hi\u1ec3u c\u00e1c bi\u1ebfn th\u1ec3 th\u00fa v\u1ecb nh\u01b0 Priority Queue, Circular Queue, Deque.<\/p>\n<p>T\u00f3m l\u1ea1i, <strong>Queue<\/strong> l\u00e0 m\u1ed9t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u n\u1ec1n t\u1ea3ng nh\u01b0ng c\u1ef1c k\u1ef3 linh ho\u1ea1t v\u00e0 m\u1ea1nh m\u1ebd. B\u1ea5t c\u1ee9 khi n\u00e0o b\u1ea1n \u0111\u1ed1i m\u1eb7t v\u1edbi b\u00e0i to\u00e1n c\u1ea7n \u0111\u1ea3m b\u1ea3o th\u1ee9 t\u1ef1 x\u1eed l\u00fd &#8220;v\u00e0o tr\u01b0\u1edbc &#8211; ra tr\u01b0\u1edbc&#8221;, duy tr\u00ec s\u1ef1 c\u00f4ng b\u1eb1ng, hay qu\u1ea3n l\u00fd c\u00e1c t\u00e1c v\u1ee5\/d\u1eef li\u1ec7u \u0111ang ch\u1edd, Queue ch\u00ednh l\u00e0 c\u00f4ng c\u1ee5 b\u1ea1n c\u1ea7n ngh\u0129 \u0111\u1ebfn. N\u1eafm v\u1eefng Queue kh\u00f4ng ch\u1ec9 gi\u00fap b\u1ea1n vi\u1ebft code hi\u1ec7u qu\u1ea3 h\u01a1n m\u00e0 c\u00f2n m\u1edf ra c\u00e1nh c\u1eeda \u0111\u1ec3 hi\u1ec3u s\u00e2u h\u01a1n v\u1ec1 c\u00e1ch c\u00e1c h\u1ec7 th\u1ed1ng m\u00e1y t\u00ednh ph\u1ee9c t\u1ea1p ho\u1ea1t \u0111\u1ed9ng.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>B\u1ea1n c\u00f3 bao gi\u1edd th\u1eafc m\u1eafc c\u00e1ch m\u00e1y t\u00ednh x\u1eed l\u00fd c\u00f4ng vi\u1ec7c theo th\u1ee9 t\u1ef1, nh\u01b0 l\u1ec7nh in hay t\u00e1c v\u1ee5 h\u1ec7 th\u1ed1ng kh\u00f4ng? \u0110\u00f3 ch\u00ednh l\u00e0 l\u00fac c\u1ea5u tr\u00fac d\u1eef li\u1ec7u Queue (H\u00e0ng \u0111\u1ee3i) ph\u00e1t huy vai tr\u00f2 quan tr\u1ecdng v\u1edbi nguy\u00ean t\u1eafc FIFO. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd \u0111i s\u00e2u gi\u1ea3i th\u00edch Queue<\/p>\n","protected":false},"author":2,"featured_media":27342,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[140],"tags":[],"class_list":["post-27330","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-lap-trinh"],"_links":{"self":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/27330","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/comments?post=27330"}],"version-history":[{"count":4,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/27330\/revisions"}],"predecessor-version":[{"id":27345,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/27330\/revisions\/27345"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media\/27342"}],"wp:attachment":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media?parent=27330"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/categories?post=27330"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/tags?post=27330"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}