leetcoder 19. Remove Nth Node From End of List

https://leetcode.com/problems/remove-nth-node-from-end-of-list/

删掉链表的倒数第n个节点

想着什么空间换时间 记录什么的。。。真的很蠢。。。。

代码一看便懂

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        ListNode *p1 = head, *p2 = head;
        while(n--){
            p1 = p1->next;
        }
        if(p1 == NULL){
            return head->next;
        }
        while(p1->next != NULL){
            p1 = p1->next;
            p2 = p2->next;
        }
        p2->next = p2->next->next;
        return head;
    }
};