21. 合并两个有序链表 about javascript-leetcode HOT 1 OPEN

// 在选择方法上总是不一致，为什么这题选递归更好呢
/*
 * @lc app=leetcode.cn id=21 lang=javascript
 * 
 * [21] 合并两个有序链表
 */

// @lc code=start
/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} list1
 * @param {ListNode} list2
 * @return {ListNode}
 */
var mergeTwoLists = function(list1, list2) {
    let l1 = list1,l2=list2;
    const prev = new ListNode(0);
    let cur = prev;
    while(l1 && l2) {
        if (l1.val > l2.val) {
            cur.next = l2;
            l2 = l2.next;
        } else {
            cur.next = l1;
            l1 = l1.next;
        }
        cur = cur.next;
    }
    cur.next = l1 || l2;
    return prev.next;
};
// @lc code=end