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) {//反转单向链表问题
              if(head==NULL||head->next==NULL)
                  return head;
              ListNode*t1, *t2, *t3;
              t1=head; t2=t1->next; t3=t2->next;
              t1->next=NULL;
              while(t3!=NULL){
                  t2->next=t1;
                  t1=t2; t2=t3; t3=t3->next;
              }
              t2->next=t1;
              return t2;
    }
};