反转单链表

#include <stack>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <string>
#include <iostream>
#include <algorithm>
#include <cstdio>

using namespace std;

struct ListNode {
    int val;
    ListNode *next;
	ListNode(){};
    ListNode(int x) : val(x), next(NULL) {}
};
 
ListNode* reverse(ListNode *head) {
	ListNode *pre = NULL, *next = NULL;
	while(head) {
		next = head->next;
		head->next = pre;
		pre = head;
		head = next;
	}
	return pre;
}

void print(ListNode* head) {
	while(head) {
		cout<<head->val<<" ";
		head=head->next;
	}
	cout<<endl;
}
int main()
{
	ListNode list[10];
	for(int i=0;i<10;i++)
		list[i].val = i;
	for(int i=0;i<9;i++)
		list[i].next=&list[i+1];
	list[9].next=NULL;
	
	cout<<"before reverse:"<<endl;
	print(&list[0]);
	cout<<"after reverse:"<<endl;
	print(reverse(&list[0]));
	
	system("PAUSE");
	return 0;
}