Merge pull request neetcode-gh#1962 from laitooo/0021-merge-two-sorte…

…d-lists.dart

Create: 0021-Merge-Two-Sorted-Lists.dart

dart/0021-merge-two-sorted-lists.dart

@@ -0,0 +1,26 @@
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *   int val;
+ *   ListNode? next;
+ *   ListNode([this.val = 0, this.next]);
+ * }
+ */
+class Solution {
+  ListNode? mergeTwoLists(ListNode? list1, ListNode? list2) {
+      ListNode? head = ListNode();
+      ListNode? cur = head;
+      while (list1 != null && list2 != null) {
+          if (list1!.val < list2!.val) {
+              cur!.next = list1;
+              list1 = list1!.next;
+          } else {
+              cur!.next = list2;
+              list2 = list2!.next;
+          }
+          cur = cur!.next;
+      }
+      cur!.next = (list1 == null) ? list2 : list1;
+      return head.next;
+  }
+}