[leedcode 189] Rotate Array

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.

[show hint]

Related problem: Reverse Words in a String II

public class Solution {
    //先翻转整个数组，然后再翻转左半部分，然后再翻转右半部分，空间复杂度O（0）
    public void rotate(int[] nums, int k) {
        k=k%nums.length;
        reverse(nums,0,nums.length-1);
        reverse(nums,0,k-1);
        reverse(nums,k,nums.length-1);
    }
    public void reverse(int[] nums,int start,int end){
        while(start<end){
            int temp=nums[start];
            nums[start]=nums[end];
            nums[end]=temp;
            start++;
            end--;
        }
    }
    //解法二：每个数字移动k次，空间复杂度O(1)，时间复杂度O(K*N),AC不通过
   /* public void rotate(int[] nums, int k){
        int len=nums.length;
        k=k%len;
        for(int i=0;i<k;i++){
            int temp=nums[len-1];
            for(int j=len-1;j>0;j--){
                nums[j]=nums[j-1];
            }
            nums[0]=temp;
        }
    }*/
    //第三种解法：coyt数组

}