leetcode--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.

旋转数组：注意里面的k是从右往左数第几个。使用的放大是三步旋转方法。

public class Solution {
    public void rotate(int[] nums, int k) {
        if (nums.length == 0) {
            return;
        }
        k = k % nums.length;
        reverse(nums,0,nums.length-1-k);
        reverse(nums,nums.length-k,nums.length-1);
        reverse(nums,0,nums.length-1);
    }

    public void reverse(int [] a,int f,int t){
        while(f<t){
            int tmp=a[f];
            a[f]=a[t];
            a[t]=tmp;
            f++;t--;
        }
    }
}