地址
https://leetcode-cn.com/problems/reverse-nodes-in-k-group/
描述
思想
代码
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
public:
ListNode* reverseKGroup(ListNode* head, int k) {
auto dummy=new ListNode (-1);
dummy->next=head;
for(auto p=dummy;;){
//判断有没有k个节点如果没有就break
auto q=p;
for(int i=0;i<k&&q;i++) q=q->next;
if(!q) break;
auto a=p->next,b=a->next;
//第一步,将k个节点进行内部翻转
for(int i=0;i<k-1;i++){
auto c=b->next;
b->next=a;
a=b;
b=c;
}
//第二步,dummy->next=3
auto c=p->next;
p->next=a;
//第三步,1->next=4
c->next=b;
p=c;
}
return dummy->next;
}
};