Rotate Array

Given an integer array nums, rotate the array to the right by k steps, where k is non-negative.

 

Example 1:

Input: nums = [1,2,3,4,5,6,7], 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: nums = [-1,-100,3,99], 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]

Solution

class Solution {

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

if(k>nums.length) {

k=k%nums.length;

}

// reverse entire array

reverse(nums, 0, nums.length-1);

// reverse first k elements in an array

reverse(nums, 0, k-1);

// reverse rest of the array

reverse(nums, k, nums.length-1);

}

public int[] reverse(int[] nums, int i, int j){

for(;i<=j; i++, j--){

int temp = nums[i];

nums[i] = nums[j];

nums[j] = temp;

}

return nums;

}

}