问题描述:
给定一个数组,将数组中的元素向右移动 k 个位置,其中 k 是非负数。
示例 1:
输入:[1,2,3,4,5,6,7]
和 k = 3 输出:[5,6,7,1,2,3,4]
解释: 向右旋转 1 步:[7,1,2,3,4,5,6]
向右旋转 2 步:[6,7,1,2,3,4,5]
向右旋转 3 步:[5,6,7,1,2,3,4]
示例 2:
输入: [-1,-100,3,99]
和 k = 2
输出: [3,99,-1,-100]
解释:
向右旋转 1 步: [99,-1,-100,3]
向右旋转 2 步: [3,99,-1,-100]
方法1:1234567 k = 2 step1:54321 76 ;step2:6712345
1 class Solution(object): 2 def rotate(self, nums, k): 3 """ 4 :type nums: List[int] 5 :type k: int 6 :rtype: void Do not return anything, modify nums in-place instead. 7 """ 8 width = len(nums) 9 if width == 0 or width == 1: 10 nums = [] 11 return 12 if width == k: 13 return 14 nums[width - k:] = nums[:width-k-1:-1] 15 nums[:width - k ] = nums[width - k - 1::-1] 16 nums.reverse()
官方:
1 class Solution(object): 2 def rotate(self, nums, k): 3 """ 4 :type nums: List[int] 5 :type k: int 6 :rtype: void Do not return anything, modify nums in-place instead. 7 """ 8 n=len(nums) 9 if n<2 or k==0: 10 return 11 k=k%n 12 nums[:k],nums[k:]=nums[n-k:],nums[:n-k]
官方二:
1 class Solution(object): 2 def rotate(self, nums, k): 3 """ 4 :type nums: List[int] 5 :type k: int 6 :rtype: void Do not return anything, modify nums in-place instead. 7 """ 8 k = k % len(nums) 9 nums[:]=nums[-k:]+nums[:-k]
2018-09-15 11:57:25