Leetcode 206. Reverse Linked List

Reverse a singly 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* current,*pnext,*prev;        if(head == NULL || head->next == NULL)            return head;        current = head;            pnext = current->next;        current->next = NULL;        while(pnext){            prev = pnext->next;            pnext->next = current;            current = pnext;            pnext = prev;        }               head = current;             return head;    }};