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。

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/*
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 pMergedHead = null;

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