leetcode-链表中的节点每k个一组翻转-81

Posted 2022-03-10 天津 唐秙

题目要求

代码实现

class Solution 
public:
    ListNode* reverseKGroup(ListNode* head, int k) 
        if(k <= 1)
            return head;
        ListNode* node = head;
        for(int i = 0; i < k; i++)
        
            if(!node)
                return head;
            node = node->next;
        
    
        ListNode* newhead = reverse(head, node);
        //经过反转之后head节点会变成一段中间的最后一个节点，头节点为newhead
        //head->next节点和下一个区间内的头节点进行连接
        head->next = reverseKGroup(node, k);
    
        return newhead;
    

private:
    //区间反转
    ListNode* reverse(ListNode* left, ListNode* right)
    
        ListNode* pre=right;
        while (left!=right) 
            ListNode* node=left->next;
            left->next=pre;
            pre = left;
            left = node;
        
        return pre;
    
    
;