Reverse Linked List

/**
 * 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 *pre = new ListNode(0),*cur = head;
        pre -> next = head;
        while (cur && cur -> next) {
            ListNode* temp = pre -> next;
            pre -> next = cur -> next;
            cur -> next = cur -> next -> next;
            pre -> next -> next = temp;
        }
        return pre -> next;
    }
};