class LRUCache{
    constructor(capacity){
        this.capacity = capacity;
        this.cache = new Map();
    }

    get(key){
        //如果没有,返回-1
        if(!this.cache.has(key)) return -1;

        const value = this.cache.get(key);
        this.cache.delete(key);
        this.cache.set(key,value)
        return value
    }

    set(key,value){
        if(this.cache.has(key)){
            this.cache.delete(key)
        }else{
            if(this.cache.size == this.capacity){
                const delKey = this.cache.keys().next().value;
                this.cache.delete(delKey)
            }
        }
        this.cache.set(key,value)
    }
}