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.

题意：旋转数组，给定数组长度n，k表示从右向左数k个数，将这k个数旋转到数组前面

分类：数组

解法1：三次反转数组即可。首先反转0到n-k-1，再反转n-k到n-1，最后将整个数组反转

public class Solution {
    public void rotate(int[] nums, int k) {
		if(nums.length==k) return;//k等于数组长度，直接返回
		if(nums.length<k) k = k%nums.length;//k大于数组长度，取k%nums.length
        rotate(nums, 0, nums.length-1-k);
        rotate(nums, nums.length-k, nums.length-1);
        rotate(nums, 0, nums.length-1);
    }
	
	public void rotate(int[] nums,int i,int j){
		while(i<j){
			int t = nums[i];
			nums[i] = nums[j];
			nums[j] = t;
			i++;j--;
		}
	}
}