题解 | #合并两个排序的链表# 最易题解

/*
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 list = new ListNode(-1);
        ListNode pre = list;
  // 判断空，然后判断两个的大小就行了，直接拼
        while (list1 != null || list2 != null) {
            if (list2 != null && (list1 == null || list2.val < list1.val)) {
                list.next = list2;
                list2 = list2.next;
            } else {
                list.next = list1;
                list1 = list1.next;
            }
            list = list.next;
        }
        return pre.next;
    }
}