1、题目描述
给定一个链表,旋转链表,将链表每个节点向右移动 k 个位置,其中 k 是非负数。
示例 1:
输入: 1->2->3->4->5->NULL, k = 2 输出: 4->5->1->2->3->NULL 解释: 向右旋转 1 步: 5->1->2->3->4->NULL 向右旋转 2 步: 4->5->1->2->3->NULL
示例 2:
输入: 0->1->2->NULL, k = 4 输出: 2->0->1->NULL 解释: 向右旋转 1 步: 2->0->1->NULL 向右旋转 2 步: 1->2->0->NULL 向右旋转 3 步: 0->1->2->NULL 向右旋转 4 步: 2->0->1->NULL
2、题解
2.1、解法一
# Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None class Solution(object): def rotateRight(self, head, k): """ :type head: ListNode :type k: int :rtype: ListNode """ node = ListNode(0) node.next = head if head == None: return None elif head.next == None: return head count = 0 cur = node.next while cur: cur = cur.next count += 1 i = 0 k = k%count while i < k: cur = node.next prev = cur while cur.next: prev = cur cur = cur.next cur.next = node.next node.next = cur prev.next = None i += 1 return node.next