/** * File: list_node.dart * Created Time: 2023-01-23 * Author: Jefferson (JeffersonHuang77@gmail.com) */ /** * Definition for a singly-linked list node */ class ListNode { int val; ListNode? next; ListNode(this.val, [this.next]); @override String toString() { return 'ListNode{val: $val, next: $next}'; } }