Leetcode206

Reverse Linked List:
Reverse a singly linked list.
Example:
Input: 1->2->3->4->5->NULL
Output: 5->4->3->2->1->NULL

Solution:

#include 

using namespace std;


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

class Solution {
public:
    ListNode* reverseList(ListNode* head) {

        ListNode* pre = NULL;
        ListNode* cur = head;
        while ( cur != NULL ) {

            ListNode* next = cur->next;

            cur->next = pre;
            pre = cur;
            cur = next;
        }

        return pre;

    }
};

int main() {

}

**总结： ** 比较简单的一种链表题，使用三个指针来完成。