2020-03-20
1.题目描述
返回倒数第 k 个节点
2.题解
首先将链表逆序,然后求出第k个即可
3.代码
#include <iostream>
using namespace std;
// Definition for singly-linked list.
struct ListNode {
int val;
ListNode *next;
ListNode(int x) : val(x), next(NULL) {}
};
class Solution {
public:
int kthToLast(ListNode* head, int k) {
ListNode* p=head,*q=p->next,*t;
p->next=NULL;
while (q){
t=q->next;
q->next=p;
p=q;
q=t;
}
int cnt=1,res;
while (p){
if (cnt==k){
res=p->val;
break;
}
p=p->next;
cnt++;
}
return res;
}
};
int main(){
Solution s;
ListNode* head=NULL, *p,*q;
int i;
p=(ListNode*)malloc(sizeof(ListNode));
p->val=1;
p->next=NULL;
head=p;
q=p;
p=(ListNode*)malloc(sizeof(ListNode));
p->val=0;
q->next=p;
p->next=NULL;
q=p;
p=(ListNode*)malloc(sizeof(ListNode));
p->val=1;
q->next=p;
p->next=NULL;
cout<<s.kthToLast(head,3)<<endl;
return 0;
}