合并两个排序的链表

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。

package 剑指Offer.合并两个排序的链表;

public class Solution {
    public ListNode Merge(ListNode list1, ListNode list2) {
        if (list1 == null) {
            return list2;
        }

        if (list2 == null) {
            return list1;
        }

        ListNode mergedListNode = null;

        if (list1.val <= list2.val) {
            mergedListNode = list1;
            mergedListNode.next = Merge(list1.next, list2);
        } else {
            mergedListNode = list2;
            mergedListNode.next = Merge(list1, list2.next);
        }

        return mergedListNode;
    }
}

class ListNode {
    int val;
    ListNode next = null;

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