Solution for Merge Two Sorted Lists #224

Fix condition in mergeTwoLists to simplify node comparison logic

Author: dohyeon2

merge-two-sorted-lists/dohyeon2.java

@@ -0,0 +1,38 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+    // TC : O(n)
+    // SC : O(n)
+    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
+        // Initialize anonymous head for result
+        ListNode result = new ListNode(0);
+        // Initialize cursor to track list
+        ListNode cursor = result;
+     
+        // If any list remains
+        while(list1 != null || list2 != null){
+            // Choose the smaller node
+            if(list2 == null 
+            || (list1 != null && list1.val <= list2.val)){
+                cursor.next = list1;
+                list1 = list1.next;
+            }else{
+                cursor.next = list2;
+                list2 = list2.next;
+            }
+            //Set the cursor to the next
+            cursor = cursor.next;
+        }
+
+        // Skip dummy head and return the actual merged list
+        return result.next;
+    }
+}