反转链表

Desicription

输入一个链表,反转链表后,输出链表的所有元素。

Solution

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/*
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) :
val(x), next(NULL) {
}
};*/
class Solution {
public:
ListNode* ReverseList(ListNode* pHead) {
ListNode* pre = nullptr;
ListNode* next = nullptr;
while(pHead) {
next = pHead->next;
pHead->next = pre;
pre = pHead;
pHead = next;
}
return pre;
}
};