Description

Submission

/**
 * 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;
        for(ListNode* ptr = head; ptr;) {
            ListNode* tmp = ptr->next;
            ptr->next = new_head;
            new_head = ptr;
            ptr = tmp;
        }
        return new_head;
    }
};