LINTCODE——K组翻转链表
思路：和翻转链表差不多，就是要注意每隔K个值打断、翻转、拼接就好了
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
/* * @param head: a ListNode * @param k: An integer * @return: a ListNode */
ListNode * reverseKGroup(ListNode * head, int k) {
// write your code here
ListNode *theadNode = new ListNode(0);
theadNode -> next = head;
ListNode *resNode = theadNode;
ListNode *curNode = head;
int cnt = 0;
while(curNode != NULL)
{
cnt++;
if(cnt == k)
{
//打断
ListNode *tcurNode = curNode;
curNode = curNode -> next;
tcurNode -> next = NULL;
//翻转
head = reverse(head);
//拼接
theadNode -> next = head;
ListNode *tail = head;
while(tail->next)
tail = tail->next;
tail -> next = curNode;
//重新定义头节点
theadNode = tail;
head = curNode;
cnt = 0;
continue;
}
curNode = curNode -> next;
}
return resNode -> next;
}
ListNode *reverse(ListNode *head)
{
if(head == NULL)
return head;
ListNode *curNode = head;
ListNode *preNode = NULL;
while(curNode != NULL)
{
ListNode *nextNode = curNode -> next;
curNode -> next = preNode;
preNode = curNode;
curNode = nextNode;
}
return preNode;
}
};