#include <stdio.h>
struct ListNode {
int val;
struct ListNode *next;
};
struct ListNode* ReverseList(struct ListNode *pHead) {
struct ListNode *pre = NULL;
struct ListNode *self = pHead;
struct ListNode *next = NULL;
while(self) {
next = self->next;
self->next = pre;
pre = self;
self = next;
}
return pre;
}
int main() {
}