Leetcode—146. LRU 缓存【中等】（哈希表+双向链表）

源代码•宸2026-01-23 8:19

2025每日刷题（242）

Leetcode---146. LRU 缓存

实现代码

go 复制代码

type node struct {
    key, val int
    prev, next *node
}

type LRUCache struct {
    capacity int
    cache map[int]*node
    head, tail *node
}

func Constructor(capacity int) LRUCache {
    head := new(node)
    tail := new(node)
    head.next = tail
    tail.prev = head
    return LRUCache{
        capacity: capacity,
        cache: make(map[int]*node, capacity),
        head: head,
        tail: tail,
    }
}


func (this *LRUCache) Get(key int) int {
    n, ok := this.cache[key]
    if !ok {
        return -1
    }
    this.moveToFront(n)
    return n.val
}


func (this *LRUCache) moveToFront(n *node) {
    this.remove(n)
    this.pushToFront(n)
}

func (this *LRUCache) remove(n *node) {
    n.prev.next = n.next
    n.next.prev = n.prev
    n.prev = nil
    n.next = nil
}

func (this *LRUCache) pushToFront(n *node) {
    n.next = this.head.next
    n.prev = this.head
    this.head.next.prev = n
    this.head.next = n
}


func (this *LRUCache) Put(key int, value int)  {
    n, ok := this.cache[key]
    if ok {
        n.val = value
        this.moveToFront(n)
        return
    }

    if len(this.cache) == this.capacity {
        back := this.tail.prev
        this.remove(back)
        delete(this.cache, back.key)
    }
    newnode := &node {
        key: key,
        val: value,
    }
    this.pushToFront(newnode)
    this.cache[key] = newnode
}


/**
 * Your LRUCache object will be instantiated and called as such:
 * obj := Constructor(capacity);
 * param_1 := obj.Get(key);
 * obj.Put(key,value);
 */

运行结果

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