leetcode_Rotate Array

leetcode_Rotate Array

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.

[show hint]

Related problem: Reverse Words in a String II

思路：

當然，一個很簡單且容易想到的思路就是直接循環移位k位即可，但每次都要移動n個元素，即總共需要移動k*n個元素

和Reverse Words in a String II題目類似，還有一種通過改變固定數目的元素就可以實現移位數組的功能，即先將1~len-k，len-k~len之間的元素逆置，最後將1~len之間的元素逆置，可以實現最後的旋轉數組的目的。

代碼：

public void rotate(int[] nums, int k) {
        if(nums==null)
            return;
		int len=nums.length;
		k=k%len;
		if(k==0)
		    return;
		int mid=len-k;
		int temp=0;
		int index=mid/2;
		for(int i=0;i