Leetcode#24Swap Nodes in Pairs

标签：example   linked   public   return   itself   

Swap Nodes in Pairs

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Question Solution 

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.

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分析：交换临近两个点，注意有奇数个点的情况

public class Solution {

    public ListNode swapPairs(ListNode head) {

        ListNode x=new ListNode(0);

        x.next=head;

        ListNode y=x;

        while(y.next!=null)

        {

            if(y.next.next==null)

                break;

            else

            {

                ListNode z=y.next.next.next;

                ListNode x1=y.next.next;

                ListNode x2=y.next;

                y.next=x1;

                x1.next=x2;

                x2.next=z;

                y=x2;

            }

        }

        return x.next;

    }

}

Leetcode#24Swap Nodes in Pairs

标签：example   linked   public   return   itself   

原文地址：http://7061299.blog.51cto.com/7051299/1652926