merge two sorted lists

Author: YuuuuuuYu

merge-two-sorted-lists/YuuuuuuYu.java

@@ -0,0 +1,34 @@
+/**
+ * Runtime: 0ms
+ * Time Complexity: O(n)
+ * - list1.length + list2.length
+ *
+ * Memory: 44.28MB
+ * Space Complexity: O(1)
+ *
+ * Approach: 빈 node를 만들고 list1, list2의 현재 값을 비교하여 더 작은 값을 추가
+ *
+ */
+class Solution {
+    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
+        if (list1 == null) return list2;
+        else if (list2 == null) return list1;
+
+        ListNode result = new ListNode();
+        ListNode currentNode = result;
+        while (list1 != null && list2 != null) {
+            if (list1.val > list2.val) {
+                currentNode.next = list2;
+                list2 = list2.next;
+            } else {
+                currentNode.next = list1;
+                list1 = list1.next;
+            }
+
+            currentNode = currentNode.next;
+        }
+
+        currentNode.next = list1 != null ? list1 : list2;
+        return result.next;
+    }
+}