LeetCode.189 Rotate Array

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本文介绍了一种将数组元素向右旋转k步的算法实现，并通过示例展示了如何将一个包含7个元素的数组[1,2,3,4,5,6,7]旋转为[5,6,7,1,2,3,4]。讨论了当k大于或等于数组长度时的特殊情况处理方法。

题目：

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

Credits:
Special thanks to @Freezen for adding this problem and creating all test cases.

分析：

class Solution {
    public void rotate(int[] nums, int k) {
         //给定数组，从右边倒数k个数，交换位置
        //如果k大于等于数组长度，对k求mod
        //思路：从需要开始移动的位置开始移动
        if(k>=nums.length){
            k=k%nums.length;
        }

        int []dummy =new int[nums.length];
        //需要移动的数赋值
        for(int i=0;i<k;i++){
            dummy[i]=nums[nums.length-k+i];
        }

        for(int i=k,j=0;i<nums.length;i++,j++){
            dummy[i]=nums[j];
        }
        //赋值
        for(int i=0;i<nums.length;i++){
            nums[i]=dummy[i];
        } 
    }
}