字符串翻转
反转链表
http://www.nowcoder.com/questionTerminal/75e878df47f24fdc9dc3e400ec6058ca
代码能力，for循环
class Solution {
public:
ListNode* ReverseList(ListNode* pHead) {
if(pHead == NULL || pHead->next == NULL){
return pHead;}
ListNode *p=NULL;
for(p;pHead;swap(p,pHead)){
swap(pHead->next,p);
}
return p;
}
};