题解 | #合并两个排序的链表#

合并排序的变形，简单题

/*
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 head = null;
        ListNode p = head;
        while(list1 != null && list2 != null) {
            ListNode node = null;
            if (list1.val < list2.val) {
                node = list1;
                list1 = list1.next;
            } else {
                node = list2;
                list2 = list2.next;
            }
            if (head == null) {
                head = node;
                p = head;
            } else {
                p.next = node;
                p = p.next;
            }
            node.next = null;
        }
        while(list1 != null) {
            ListNode node = list1;
            if (head == null) {
                head = node;
                p = head;
            } else {
                p.next = node;
                p = p.next;
            }
            list1 = list1.next;
            node.next = null;
        }
        while(list2 != null) {
            ListNode node = list2;
            if (head == null) {
                head = node;
                p = head;
            } else {
                p.next = node;
                p = p.next;
            }
            list2 = list2.next;
            node.next = null;
        }
        return head;
    }
}