LINTCODE——K组翻转链表

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;    }};