Java [Leetcode 189]Rotate Array

题目描述：

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.

解题思路：

牺牲空间复杂度的话可以考虑开辟新的数组空间，然后依次移动即可；

本方法只用一个临时变量存放临时数据，然后依次的交换数据，如图所示：

但是注意会陷入局部循环的局面，这时将相应的下标后移一位。

public class Solution {
    public void rotate(int[] nums, int k) {
    	int length = nums.length;
    	if(length == 0)
    		return;
    	k = k % length;
    	int head = 0, curIndex = 0, nextIndex;
    	int curValue = nums[0], nextValue;
    	for(int i = 0; i < length; i++){
    		if(curIndex == head && i > 0){ //finish a circle,move to another circle
    			curIndex++;
    			head++;
    			curValue = nums[curIndex];
    		}
    		nextIndex = (curIndex + k) % length;
    		nextValue = nums[nextIndex];
    		nums[nextIndex] = curValue;
    		curIndex = nextIndex;
    		curValue = nextValue;
    	}
    }
}

　　

代码如下：