//

// main.cpp

// leetcode024

//

// Created by 萧天牧 on 17/2/27.

// Copyright © 2017年 萧天牧. All rights reserved.

//

#include <iostream>

using namespace std;

struct ListNode {

int val;

ListNode *next;

ListNode(int x) : val(x), next(NULL) {}

};

ListNode* swap(ListNode* A,ListNode* B){

if(B == NULL)

return A;

A->next = B -> next;

B->next = A;

return B;

}

ListNode* swapPairs(ListNode* head) {

if(head == NULL || head -> next == NULL)

return head;

ListNode *shaobing = new ListNode(0);

shaobing ->next = head;

ListNode *tmp = shaobing;

while(tmp && tmp->next){

tmp -> next = swap(tmp ->next, tmp -> next -> next);

tmp = tmp ->next -> next;

}

return shaobing->next;

}

int main(int argc, const char * argv[]) {

// insert code here...

std::cout << "Hello, World!\n";

return 0;

}