class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode *cur, *newHead;
        cur = head;
        newHead = NULL;
        while (cur) {
            ListNode *tmp = cur->next;
            cur->next = newHead;
            newHead = cur;
            cur = tmp;
        }
        return newHead;
    }
};