- GG. Took some time. Need to practice linked list.

_006_mergeTwoSortedLists.js

@@ -0,0 +1,34 @@
+/**
+ * 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) {
+    const mergedHead = new ListNode(-Infinity);
+    let currentMerged = mergedHead;
+    let pointer1 = list1;
+    let pointer2 = list2;
+
+    while (pointer1 && pointer2) {
+        if (pointer1.val <= pointer2.val) {
+            currentMerged.next = pointer1;
+            pointer1           = pointer1.next;
+        } else {
+            currentMerged.next = pointer2;
+            pointer2           = pointer2.next;
+        }
+
+        currentMerged = currentMerged.next;
+    }
+
+    if (pointer1) currentMerged.next = pointer1;
+    if (pointer2) currentMerged.next = pointer2;
+
+    return mergedHead.next;
+};