Java Program to Check if all array elements can be converted to pronic numbers by rotating digits

Given an array arr[] of size N, the task is to check if it is possible to convert all of the array elements to a pronic number by rotating the digits of array elements any number of times.

Examples:

Input: {321, 402, 246, 299} 
Output: True 
Explanation:
arr[0] ? Right rotation once modifies arr[0] to 132 (= 11 × 12). 
arr[1] ? Right rotation once modifies arr[0] to 240 (= 15 × 16). 
arr[2] ? Right rotation twice modifies arr[2] to 462 (= 21 × 22). 
arr[3] ? Right rotation twice modifies arr[3] to 992 (= 31 × 32).

Input: {433, 653, 402, 186}
Output: False

Approach: Follow the steps below to solve the problem:

• Traverse the array and check for each array element, whether it is possible to convert it to a pronic number.
• For each array element, apply all the possible rotations and check after each rotation, whether the generated number is pronic or not.
• If it is not possible to convert any array element to a pronic number, print “False”.
• Otherwise, print “True”.

Below is the implementation of the above approach:

Java

// Java program for the above approach

import java.io.*;
import java.lang.*;
import java.util.*;

class GFG {

  // function to check Pronic Number
  static boolean isPronic(int x)
  {

    for (int i = 0; i < (int)(Math.sqrt(x)) + 1; i++) {

      // Checking Pronic Number
      // by multiplying consecutive
      // numbers
      if (x == i * (i + 1)) {
        return true;
      }
    }

    return false;
  }

  // Function to check if any permutation
  // of val is a pronic number or not
  static boolean checkRot(int val)
  {
    String temp = Integer.toString(val);
    for (int i = 0; i < temp.length(); i++)
    {
      if (isPronic(Integer.parseInt(temp)) == true) {
        return true;
      }

      temp = temp.substring(1) + temp.charAt(0);
    }
    return false;
  }

  // Function to check if all array
  // elements can be converted to
  // a pronic number or not
  static boolean check(int arr[], int N)
  {

    // Traverse the array
    for (int i = 0; i < N; i++)
    {

      // If current element
      // cannot be converted
      // to a pronic number
      if (checkRot(arr[i]) == false)
      {
        return false;
      }
    }
    return true;
  }

  // Driver code
  public static void main(String[] args)
  {

    // Given array
    int arr[] = { 321, 402, 246, 299 };
    int N = arr.length;

    // Function call
    System.out.println(
      (check(arr, N) ? "True" : "False"));
  }
}

// This code is contributed by Kingash.

Output:

True

Time Complexity: O(N^3/2)
Auxiliary Space: O(1)

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