Leetcode之swap Nodes In Pairs

28 June 2014

Swap Nodes in Pairs

Given a linked list, swap every two adjacent nodes and return its head.

For example, Given 1->2->3->4, you should return the list as 2->1->4->3.

Your algorithm should use only constant space. You may not modify the values in the list, only nodes itself can be changed.

解法：链表题目首先想到的就是递归，这题就是简单的递归，突然想起来了，转置链表，用递归就能很快实现。

代码如下：

//{java}
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode swapPairs(ListNode head) {
        if(head==null||head.next==null)
            return head;
        ListNode q = head;
        ListNode p = head.next;
        ListNode k = swapPairs(p.next);
        q.next=k;
        p.next=q;
        return p;
    }
}

LeetCode 47

LeetCode，面试，链表，，递归，顺序调换 2

Leetcode之swap Nodes In Pairs 调换链表每对节点的位置

Swap Nodes in Pairs