leecode/backlog/21.merge-two-sorted-lists.js
2020-05-22 18:17:19 +08:00

72 lines
1.4 KiB
JavaScript

/*
* @lc app=leetcode id=21 lang=javascript
*
* [21] Merge Two Sorted Lists
*
* https://leetcode.com/problems/merge-two-sorted-lists/description/
*
* algorithms
* Easy (46.02%)
* Total Accepted: 562.7K
* Total Submissions: 1.2M
* Testcase Example: '[1,2,4]\n[1,3,4]'
*
* Merge two sorted linked lists and return it as a new list. The new list
* should be made by splicing together the nodes of the first two lists.
*
* Example:
*
* Input: 1->2->4, 1->3->4
* Output: 1->1->2->3->4->4
*
*
*/
/**
* Definition for singly-linked list.
* function ListNode(val) {
* this.val = val;
* this.next = null;
* }
*/
/**
* @param {ListNode} l1
* @param {ListNode} l2
* @return {ListNode}
*/
var mergeTwoLists = function(l1, l2) {
let current = new ListNode();
const dummy = current;
while (l1 || l2) {
if (!l1) {
current.next = l2;
return dummy.next;
} else if (!l2) {
current.next = l1;
return dummy.next;
}
if (l1.val <= l2.val) {
current.next = l1;
l1 = l1.next;
} else {
current.next = l2;
l2 = l2.next;
}
current = current.next;
}
return dummy.next;
// if (l1 === null) return l2;
// if (l2 === null) return l1;
// if (l1.val < l2.val) {
// l1.next = mergeTwoLists(l1.next, l2);
// return l1;
// } else {
// l2.next = mergeTwoLists(l1, l2.next);
// return l2;
// }
};