25. Reverse Nodes in k-Group
来源:互联网 发布:python 私有成员获取值 编辑:程序博客网 时间:2024/05/18 00:52
Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.
If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is.
You may not alter the values in the nodes, only nodes itself may be changed.
Only constant memory is allowed.
For example,
Given this linked list: 1->2->3->4->5
For k = 2, you should return: 2->1->4->3->5
For k = 3, you should return: 3->2->1->4->5
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {public: ListNode* reverseKGroup(ListNode* head, int k) { if(!head) return NULL; int len = 0; ListNode *cur = head; while(cur) { ++len; cur = cur->next; } //if the length of the list is smaller than k,return if(len<k) return head; ListNode *dummy = new ListNode(INT_MAX); dummy->next = head; ListNode *prev = dummy; cur = head; ListNode *next = cur->next; //save value of k in a tmp variable int kOrigin = k; //revers the k list nodes while(cur && k>0) { cur->next = prev; prev = cur; cur = next; if(next) next = next->next; --k; } //set the pointers dummy->next = prev; head->next = NULL; //recurse if(cur) head->next = reverseKGroup(cur,kOrigin); return dummy->next; }};
跟Swap Nodes in Pairs思路类似,也要用递归,只不过把swap换成了reverse;
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {public: ListNode* reverseKGroup(ListNode* head, int k) { if(!head || !head->next || k<=1) return head; ListNode *p = head; //计算链表的长度 int len = 0; while(p) { len++; p = p->next; } //如果k>len,直接返回输入链表 if(k > len) return head; p = NULL; ListNode *q = head; int kTmp = k; //将长度为k的链表reverse while(q && kTmp>0) { ListNode *tmp = q->next; q->next = p; p = q; q = tmp; kTmp--; } //如果剩余链表的长度>k,则继续reverse if(len-k >= k) head->next = reverseKGroup(q,k); //否则,将后续链表直接接上 else head->next = q; return p; }};
0 0
- [LeetCode]25.Reverse Nodes in k-Group
- LeetCode --- 25. Reverse Nodes in k-Group
- LeetCode 25.Reverse Nodes in k-Group
- [Leetcode] 25. Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- 【LeetCode】25.Reverse Nodes in k-Group
- [leetcode] 25.Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- Leetcode-25.Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- leetcode 25. Reverse Nodes in k-Group
- leetcode 25. Reverse Nodes in k-Group
- 25. Reverse Nodes in k-Group
- 位运算
- Magic File Renamer算法分析(注册机没能写出)
- Graphchi介绍及BFS实现
- [Java] Webservice之定制发布WSDD教程 (二)
- 基于OpenStack的虚拟机在线迁移
- 25. Reverse Nodes in k-Group
- linux 常用命令
- 学习js的笔记--检测类型
- WARNING: erroneous pipeline: no element "ffdec_h264"解决方案
- oracle里面的long,long raw,raw,clob,blob区别 .
- Sql server中递归的用法
- Linux ALSA声卡驱动之五:移动设备中的ALSA(ASoC)
- jsp的各种路径获取
- hdu 1864 最大报销额 (01背包)