Rotating an array by D places GFG

 package com.company;

import java.util.Arrays;

public class Array9 {
    //    Efficient method
    public static int[] reverse(int[] arr, int low, int high) {
        while (high > low) {
            int a = arr[low];
            arr[low] = arr[high];
            arr[high] = a;
            low++;
            high--;
        }
        return arr;
    }

    public static int[] leftRotate(int[] arr, int d) {
        int n = arr.length;
        reverse(arr,0,d-1);
        reverse(arr,d,n-1);
        reverse(arr,0,n-1);
        return arr;
    }
//       Right rotate an array by one
//     public static int[] rotateAnArrayByOne(int[] arr, int d) {
//        int n = arr.length;
//        int a = arr[n - d];
//        for (int i = 0; i < n - d; i++) {
//            arr[n - d - i] = arr[n - d - i - 1];
//        }
//        arr[0] = a;
//        return arr;
//    }
//
//    //    Efficient solution by me
//    public static int[] rotating(int[] arr, int d) {
//        int n = arr.length;
//        for (int i = 0; i < d; i++) {
//            int a = arr[i];
//            arr[i] = arr[n - d + i];
//            arr[n - d + i] = a;
//        }
//        rotateAnArrayByOne(arr,d);
//        return arr;
//    }

    //    Naive solution
    public static int[] leftRotateByOne(int[] arr) {
        int n = arr.length;
        int temp = arr[0];
        for (int i = 1; i < n; i++) {
            arr[i - 1] = arr[i];
        }
        arr[n - 1] = temp;
        return arr;
    }

    public static int[] leftRotateAnArrayByD(int[] arr, int d) {
        int n = arr.length;
        for (int i = 0; i < d; i++) {
            leftRotateByOne(arr);
        }
        return arr;
    }

    //    Left rotate an array by D places  --->MY SOLUTION
    public static int[] rotate(int[] arr, int d) {
        int n = arr.length;
        int[] array = new int[d];
        for (int j = 0; j < d; j++) {
            array[j] = arr[j];
        }
        for (int i = 0; i < n - d; i++) {
            arr[i] = arr[d + i];
        }
        for (int i = 0; i < d; i++) {
            arr[n - d + i] = array[i];
        }
        return arr;
    }

    public static void main(String[] args) {
        int[] ar = {10, 5, 30, 15};
        System.out.println(Arrays.toString(leftRotate(ar, 3)));
    }
}