链表练习

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode *new_head = NULL;
        while(head)
        {
            ListNode *next = head->next;
            head->next = new_head;
            new_head=head;
            head=next;
        }
        return new_head;
        
    }
};