题解 | #合并两个排序的链表#

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

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode Merge(ListNode list1, ListNode list2) {
        if (list1 == null) {
            return list2;
        }
        if (list2 == null) {
            return list1;
        }

        ListNode list = null ;

        int len = 0;
        ListNode start = list1;
        while (start != null) {
            start = start.next;
            len++;
        }
        ListNode temp = null;
        ListNode cur = null;
        while (list1 != null && list2 != null) {
            // ListNode cur = list;
            if (list1.val > list2.val) {
                temp = list2;
                if (list == null) {
                    list = cur = temp;
                } else {
                    cur.next = temp;
                    cur = cur.next;
                }
                list2 = list2.next;
            } else {
                temp = list1;
                if (list == null) {
                    list = cur = temp;
                } else {
                    cur.next = temp;
                    cur = cur.next;
                }
                list1 = list1.next;
            }
        }
        if (list1 == null) {

            cur.next = list2;

        }
        if (list2 == null) {

            cur.next = list1;

        }
        return list;
    }
}