Reverse a singly linked list.
以1—>2->3->4为例，链表反转的过程如下：
第一次循环结束：
head: 2->3->4->NULL
newhead: 1->NULL
第二次循环结束：
head: 3->4->NULL
newhead: 2->1->NULL
第三次循环结束：
head: 4->NULL
newhead: 3->2->1->NULL
第四次循环结束：
head: NULL
newhead: 4->3->2->1->NULL
1 class Solution { 2 public: 3 ListNode* reverseList(ListNode *head) { 4 ListNode *newHead = NULL; 5 while (head) { 6 ListNode *nextNode = head->next; 7 head->next = newHead; 8 newHead = head; 9 head = nextNode; 10 } 11 return newHead; 12 } 13 };
1 class Solution { 2 public: 3 ListNode* reverseList(ListNode *head) { 4 return reverseListIter(head, NULL); 5 } 6 ListNode *reverseListIter(ListNode *head, ListNode *newhead) { 7 if (head == NULL) { 8 return newhead; 9 } 10 ListNode *nextNode = head->next; 11 head->next = newhead; 12 return reverseListIter(nextNode, head); 13 } 14 };
http://www.2cto.com/kf/201601/485759.html
原文：http://www.cnblogs.com/sindy/p/6806514.html