LeetCode(67)-Rotate Array

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题目：

Rotate an array of n elements to the right by k steps.For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].Note:Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.

思路：

题意：要求对给定长度的整形数组n进行平移，给定k，就平移3个位置（循环）
要求是在o（1）的空间，不能考虑数组的复制了，根据算法，这个平移转化为逆序。reverse（nums，0，n-k-1），reverse（nums，n-k，n-1），reverse（nums，0，n-1）等价，写一个reverse的函数。

代码：

public class Solution {    public void reverse(int[] nums,int start,int end){            while(start < end){                int tmp = nums[start];                nums[start] = nums[end];                nums[end] = tmp;                start++;                end--;            }        }    public void rotate(int[] nums, int k) {        if(nums.length == 0){            return;        }           int n = nums.length;        k = k%n;        reverse(nums,0,n-k-1);        reverse(nums,n-k,n-1);        reverse(nums,0,n-1);    }}

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