LeetCode-Merge Two Sorted Lists

Merge Two Sorted Lists

##题目

####Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

##解题思路
该题是将两个有序链表进行合并，方法很简单，只要对每个链表维持一个指针，然后比较大小，进行链表的链接操作就行了，该题是Merge k Sorted Lists这题的子过程。

##算法代码
代码采用JAVA实现：

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/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if(l1==null)
        	return l2;
        if(l2==null)
        	return l1;
        ListNode l3=new ListNode(0);
        ListNode p=l1;
        ListNode q=l2;
        ListNode k=l3;
        while(p!=null && q!=null)
        {
        	if(p.val<=q.val)
        	{
        		k.next=p;
        		p=p.next;
        		k=k.next;
        	}else{
        		k.next=q;
        		q=q.next;
        		k=k.next;
        	}
        }
        if(p!=null)
        	k.next=p;
        if(q!=null)
        	k.next=q;
        return l3.next;
    }
}

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