feat: merge two sorted lists

Author: anniemon

merge-two-sorted-lists/anniemon.js

@@ -0,0 +1,39 @@
+/**
+ * 시간 복잡도:
+ *   list1의 길이가 m, list2의 길이가 n이면
+ *   포인터가 최대 m + n만큼 순회하므로 O(m + n)
+ * 공간 복잡도:
+ *   포인터를 사용하므로 O(1)
+ */
+/**
+ * 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 head = new ListNode(0, null);
+  let pointer = head;
+  while(list1 && list2) {
+      if(list1.val < list2.val) {
+          pointer.next = list1;
+          list1 = list1.next;
+      } else {
+          pointer.next = list2;
+          list2 = list2.next;
+      }
+      pointer = pointer.next;
+  }
+  if(list1) {
+      pointer.next = list1;
+  } else {
+      pointer.next = list2;
+  }
+  return head.next;
+};