Create 21-Merge-Two-Sorted-Lists.js

javascript/21-Merge-Two-Sorted-Lists.js

@@ -0,0 +1,28 @@
+/**
+ * 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(l1, l2) {
+ let nullNode = { val : 0, next : null};
+ let prev = nullNode;
+ while (l1 && l2) {
+ if (l1.val >= l2.val) {
+ prev.next = l2;
+ l2 = l2.next;
+ } else {
+ prev.next = l1;
+ l1 = l1.next;
+ }
+ prev = prev.next; 
+ }
+ prev.next = l1 || l2;
+ return nullNode.next;
+};