/* public class ListNode { int val; ListNode next = null;

ListNode(int val) {
    this.val = val;
}

}*/ public class Solution { public ListNode Merge(ListNode list1,ListNode list2) { ListNode node = new ListNode(0); ListNode node1 = node; while (list1 != null && list2 != null) { if (list1.val < list2.val) { node.next = list1; node = node.next; list1 = list1.next; } else { node.next = list2; node = node.next; list2 = list2.next; } } while (list1 != null) { node.next = list1; node = node.next; list1 = list1.next; } while (list2 != null) { node.next = list2; node = node.next; list2 = list2.next; } return node1.next; } }