Class LinkedList

javascript/0460-lfu-cache.js:11–56

}

class LinkedList {
    constructor() {
        this.map = new Map();
        this.Right = new ListNode(null);
        this.Left = new ListNode(null, this.Right);
        this.Right.prev = this.Left;
    }

    len() {
        return this.map.size;
    }

    pop(val) {
        if (this.map.has(val)) {
            let node = this.map.get(val);

            // save
            let prevNode = node.prev;
            // delete
            prevNode.next = node.next;
            prevNode.next.prev = prevNode;
            this.map.delete(val);
        }
    }

    popleft() {
        let data = this.Left.next.val;
        this.Left.next = this.Left.next.next;
        this.Left.next.prev = this.Left;
        this.map.delete(data);
        return data;
    }

    pushRight(val) {
        let newNode = new ListNode(val, this.Right);
        newNode.prev = this.Right.prev;
        newNode.prev.next = newNode;
        this.Right.prev = newNode;
        this.map.set(val, newNode);
    }

    update(val) {
        this.pop(val);
        this.pushRight(val);
    }
}

/**
 * @param {number} capacity