题解 | #反转链表# 头插法

/*
struct ListNode {
	int val;
	struct ListNode *next;
	ListNode(int x) :
			val(x), next(NULL) {
	}
};*/
class Solution {
public:
    ListNode* ReverseList(ListNode* pHead) {
		if(!pHead || !pHead->next) return pHead;
		auto re = new ListNode(-1);
		while(pHead) {
			auto temp = pHead->next;
			pHead->next = re->next;
			re->next = pHead;
			pHead = temp;
		}
		return re->next;

    }
};