{"id":927,"date":"2025-12-12T01:53:46","date_gmt":"2025-12-11T17:53:46","guid":{"rendered":"https:\/\/www.guanhaobo.cn\/?p=927"},"modified":"2025-12-12T01:53:46","modified_gmt":"2025-12-11T17:53:46","slug":"leetcode-146-lru-%e7%bc%93%e5%ad%98","status":"publish","type":"post","link":"https:\/\/www.guanhaobo.cn\/?p=927","title":{"rendered":"LeetCode 146 \u2014 LRU \u7f13\u5b58"},"content":{"rendered":"

\u9898\u76ee\u63cf\u8ff0<\/h1>\n

\u8bf7\u4f60\u8bbe\u8ba1\u5e76\u5b9e\u73b0\u4e00\u4e2a\u6ee1\u8db3 LRU (\u6700\u8fd1\u6700\u5c11\u4f7f\u7528) \u7f13\u5b58 \u7ea6\u675f\u7684\u6570\u636e\u7ed3\u6784\u3002
\n\u5b9e\u73b0 LRUCache \u7c7b\uff1a
\nLRUCache(int capacity) \u4ee5 \u6b63\u6574\u6570 \u4f5c\u4e3a\u5bb9\u91cf capacity \u521d\u59cb\u5316 LRU \u7f13\u5b58
\nint get(int key) \u5982\u679c\u5173\u952e\u5b57 key \u5b58\u5728\u4e8e\u7f13\u5b58\u4e2d\uff0c\u5219\u8fd4\u56de\u5173\u952e\u5b57\u7684\u503c\uff0c\u5426\u5219\u8fd4\u56de -1 \u3002
\nvoid put(int key, int value) \u5982\u679c\u5173\u952e\u5b57 key \u5df2\u7ecf\u5b58\u5728\uff0c\u5219\u53d8\u66f4\u5176\u6570\u636e\u503c value \uff1b\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5219\u5411\u7f13\u5b58\u4e2d\u63d2\u5165\u8be5\u7ec4 key-value \u3002\u5982\u679c\u63d2\u5165\u64cd\u4f5c\u5bfc\u81f4\u5173\u952e\u5b57\u6570\u91cf\u8d85\u8fc7 capacity \uff0c\u5219\u5e94\u8be5 \u9010\u51fa \u6700\u4e45\u672a\u4f7f\u7528\u7684\u5173\u952e\u5b57\u3002
\n\u51fd\u6570 get \u548c put \u5fc5\u987b\u4ee5 O(1) \u7684\u5e73\u5747\u65f6\u95f4\u590d\u6742\u5ea6\u8fd0\u884c\u3002<\/p>\n

\u9898\u76ee\u5206\u6790<\/h1>\n

\u4f7f\u7528\u53cc\u5411\u94fe\u8868\u6765\u7ef4\u62a4\u6570\u636e\uff0c\u4f7f\u7528 HashMap \u5b9e\u73b0\u5bf9 key \u7684 O(1) \u8bbf\u95ee.
\n\u6bcf\u6b21\u8bbf\u95ee\u4e00\u4e2a\u6570\u636e\uff08get \u6216 put\uff09\uff0c\u5c31\u628a\u5176\u79fb\u52a8\u5230\u94fe\u8868\u7684\u5c3e\u90e8\uff0c\u800c\u94fe\u8868\u5934\u90e8\u5373\u662f\u6700\u4e45\u672a\u8bbf\u95ee\u7684\u5143\u7d20\u3002\u5f53\u5bb9\u91cf\u8d85\u51fa\u8bbe\u5b9a\u65f6\uff08put \u65f6\u5224\u65ad\uff09\uff0c\u5c06\u5934\u90e8\u5143\u7d20\u5728\u94fe\u8868\u548c HashMap \u4e2d\u540c\u6b65\u79fb\u9664\u3002
\n\u4f7f\u7528\u865a\u62df\u5934\u7ed3\u70b9\u548c\u5c3e\u7ed3\u70b9\uff0c\u4ee3\u7801\u5199\u8d77\u6765\u66f4\u7b80\u5355\u3002<\/p>\n

Java<\/h1>\n
public class LruCache {\n\n    private class Node {\n        int key;\n        int value;\n        Node pre;\n        Node next;\n\n        Node(int key, int value) {\n            this.key = key;\n            this.value = value;\n        }\n    }\n\n    private HashMap<Integer, Node> map = new HashMap<>();\n    \/\/ \u865a\u62df\u5934\/\u5c3e\u7ed3\u70b9\n    private Node head = new Node(0, 0); \/\/ \u65e7\n    private Node tail = new Node(0, 0); \/\/ \u65b0\n    private int capacity;\n\n    public LruCache(int capacity) {\n        this.capacity = capacity;\n        head.next = tail;\n        tail.pre = head;\n    }\n\n    public int get(int key) {\n        if (!map.containsKey(key)) {\n            return -1;\n        }\n\n        Node node = map.get(key);\n        moveToTail(node);\n        return node.value;\n    }\n\n    public void put(int key, int value) {\n        Node node;\n        if (map.containsKey(key)) {\n            node = map.get(key);\n            node.value = value;\n        } else {\n            node = new Node(key, value);\n            map.put(key, node);\n        }\n        moveToTail(node);\n        if (map.size() > capacity) {\n            removeEldest();\n        }\n    }\n\n    private void moveToTail(Node node) {\n        Node pre = node.pre;\n        Node next = node.next;\n        if (pre != null) {\n            pre.next = next;\n            next.pre = pre;\n        }\n        tail.pre.next = node;\n        node.pre = tail.pre;\n        node.next = tail;\n        tail.pre = node;\n    }\n\n    private void removeEldest() {\n        map.remove(head.next.key);\n        head.next = head.next.next;\n        head.next.pre = head;\n    }\n}\n<\/code><\/pre>\n
Kotlin<\/h1>\n
class LruCache(var capacity: Int) {\n\n    private val map = HashMap<Int, Node>()\n    private val head = Node(0, 0) \/\/ \u65e7\n    private val tail = Node(0, 0) \/\/ \u65b0\n\n    init {\n        head.next = tail\n        tail.pre = head\n    }\n\n    fun get(key: Int): Int {\n        if (!map.containsKey(key)) {\n            return -1\n        }\n        val node = map[key]!!\n        moveToTail(node)\n        return node.value\n    }\n\n    fun put(key: Int, value: Int) {\n        if (map.containsKey(key)) {\n            val node = map[key]!!\n            node.value = value\n            moveToTail(node)\n        } else {\n            val node = Node(key, value)\n            map[key] = node\n            moveToTail(node)\n            if (map.size > capacity) {\n                removeEldest()\n            }\n        }\n    }\n\n    private fun moveToTail(node: Node) {\n        if (node.pre != null) {\n            val pre = node.pre\n            val next = node.next\n            pre?.next = next\n            next?.pre = pre\n        }\n\n        tail.pre?.next = node\n        node.pre = tail.pre\n        node.next = tail\n        tail.pre = node\n    }\n\n    private fun removeEldest() {\n        val node = head.next\n        head.next = node?.next\n        head.next?.pre = head\n        map.remove(node?.key!!)\n    }\n\n    private data class Node(var key: Int, var value: Int, var pre: Node? = null, var next: Node? = null)\n}\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\u9898\u76ee\u63cf\u8ff0 \u8bf7\u4f60\u8bbe\u8ba1\u5e76\u5b9e\u73b0\u4e00\u4e2a\u6ee1\u8db3 LRU (\u6700\u8fd1\u6700\u5c11\u4f7f\u7528) \u7f13\u5b58 \u7ea6\u675f\u7684\u6570\u636e\u7ed3\u6784\u3002 \u5b9e\u73b0 LRUCache \u7c7b […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[20,74,52,84],"class_list":["post-927","post","type-post","status-publish","format-standard","hentry","category-algo","tag-leetcode","tag-74","tag-52","tag-84"],"_links":{"self":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/927","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=927"}],"version-history":[{"count":1,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/927\/revisions"}],"predecessor-version":[{"id":928,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/927\/revisions\/928"}],"wp:attachment":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=927"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=927"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=927"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}