java-coding-ninjas/recursion1/CheckSortedArray.java at master · avinashbest/java-coding-ninjas · GitHub

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package recursion1;

import java.util.Scanner;

public class CheckSortedArray {

public static boolean checkSorted(int[] arr) {

if (arr.length <= 1) {

return true;

}

if (arr[0] > arr[1]) {

return false;

}

/*breaking the bigger array into smaller array everytime*/

int[] smallArr = new int[arr.length - 1];

/*copying the array*/

for (int i = 1; i < arr.length; i++) {

smallArr[i - 1] = arr[i];

}

return checkSorted(smallArr);

}

/*this functions check whether the array is sorted or in the range startIndex to arr.length*/

private static boolean checkSortedOptimised(int[] arr, int startIndex) {

/*if there is only one element which is obviously sorted by default*/

if (startIndex >= arr.length - 1) {

return true;

}

/*if first element is of the array is greater than the second element its obviously sorted.*/

if (arr[startIndex] > arr[startIndex + 1]) {

return false;

}

return checkSortedOptimised(arr, startIndex + 1);

}

/*Recursion and the helper function*/

public static boolean checkSortedOptimised(int[] arr) {

return checkSortedOptimised(arr, 0);

}

public static int[] takeInput() {

Scanner scan = new Scanner(System.in);

System.out.print("Size of the Array? ");

int size = scan.nextInt();

int[] arr = new int[size];

System.out.println("Enter elements of the Array: ");

for (int i = 0; i < size; i++) {

arr[i] = scan.nextInt();

}

return arr;

}

public static void main(String[] args) {

int[] arr = takeInput();

System.out.println(checkSortedOptimised(arr));

}

java-coding-ninjas/recursion1/CheckSortedArray.java at master · avinashbest/java-coding-ninjas · GitHub

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