138.复制带随机指针的链表.js

/*
 * @lc app=leetcode.cn id=138 lang=javascript
 *
 * [138] 复制带随机指针的链表
 */

// @lc code=start
/**
 * // Definition for a Node.
 * function Node(val, next, random) {
 *    this.val = val;
 *    this.next = next;
 *    this.random = random;
 * };
 */

/**
 * @param {Node} head
 * @return {Node}
 */
var copyRandomList = function (head) {
    if (!head) {
        return null;
    }
    const clones = new Map();
    let n = head;
    while (n) {
        clones.set(n, new Node(n.val));
        n = n.next
    }
    n = head;
    while (n) {
        clones.get(n).next = clones.get(n.next) || null;
        clones.get(n).random = clones.get(n.random) || null;
        n = n.next
    }
    return clones.get(head);
};
// @lc code=end