Rotate Array

中文说明

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Give an array ,rotate the array to the right by k steps,where k is non-negative

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Example 1

Input: [1,2,3,4,5,6,7] and k = 3
Output: [5,6,7,1,2,3,4]
Explanation:
rotate 1 steps to the right: [7,1,2,3,4,5,6]
rotate 2 steps to the right: [6,7,1,2,3,4,5]
rotate 3 steps to the right: [5,6,7,1,2,3,4]

Example 2

Input: [-1,-100,3,99] and k = 2
Output: [3,99,-1,-100]
Explanation:
rotate 1 steps to the right: [99,-1,-100,3]
rotate 2 steps to the right: [3,99,-1,-100]

Note

• Try to come up as many solution as you can , there are at least 3 different ways to solve the problem.

• Cloud you do it in-place with O(1) extra space?

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Answer Here

/**
 * @author Loucianus
 */
public class RotateArray {

    public void rotate(int[] nums, int k) {

        int modK = k % nums.length;

        if(nums.length == 0) {
            return;
        }

        metathesis(nums, nums.length - modK, nums.length - 1);
        metathesis(nums, 0, nums.length - modK -1);
        metathesis(nums, 0, nums.length - 1);
    }

    private void metathesis(int[] nums, int begin, int end) {
        while(begin < end) {
            nums[begin] = nums[begin] ^ nums[end];
            nums[end] = nums[begin] ^ nums[end];
            nums[begin] = nums[begin] ^ nums[end];
            begin++;
            end--;
        }
    }
}