Question

输入两个单调递增的链表，输出两个链表合成后的链表，当然我们需要合成后的链表满足单调不减规则。

/*
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 result = new ListNode(-1);
    ListNode head = result;
    while(list1 != null && list2 != null){
      if(list1.val < list2.val){
        result.next = list1;
        list1 = list1.next;
      }else{
        result.next = list2;
        list2 = list2.next;
      }
      result = result.next;
    }
    if(list1 == null) result.next = list2;
    if(list2 == null) result.next = list1;
    return head.next;
  }
}