Java Lambda Expression - HackerRank Solution

Java Lambda Expression - HackerRank Solution

Hello Friends, How are you? Today I will solve the HackerRank Java Lambda Expression - Problem with a straightforward explanation. In this article, you will get more than one approach to solve this problem. So let's start-

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HackerRank Java Lambda Expression - Problem Statement

This Java 8 challenge tests your knowledge of Lambda expressions!

Write the following methods that return a lambda expression performing a specified action:

1. PerformOperation isOdd(): The lambda expression must return true if a number is odd or false if it is even.
2. PerformOperation isPrime(): The lambda expression must return true if a number is prime or false if it is composite.
3. PerformOperation isPalindrome(): The lambda expression must return true if a number is a palindrome or false if it is not.

Input Format

Input is handled for you by the locked stub code in your editor.

Output Format

The locked stub code in your editor will print T lines of output.

Sample Input

The first line contains an integer, T (the number of test cases).

The T subsequent lines each describe a test case in the form of 2 space-separated integers:

The first integer specifies the condition to check for (1 for Odd/Even, 2 for Prime, or 3 for Palindrome). The second integer denotes the number to be checked.

5 1 4 2 5 3 898 1 3 2 12 {codeBox}

Sample Output

EVEN PRIME PALINDROME ODD COMPOSITE {codeBox}

Java Lambda Expression HackerRank Solution

Java Lambda Expression - Hacker Rank Solution

Approach I: Java Lambda Expression - Solution HackerRank

// ========================
//       Information
// ========================

// Name: Java Lambda Expression HackerRank Problem
// Direct Link: https://www.hackerrank.com/challenges/java-lambda-expressions/problem
// Difficulty: Medium
// Max Score: 30
// Language: Java 8

// ========================
//         Solution Start
// ========================

// Java Lambda Expression - Hacker Rank Solution Start

import java.io.*;
import java.util.*;
interface PerformOperation {
 boolean check(int a);
}
class MyMath {
 public static boolean checker(PerformOperation p, int num) {
  return p.check(num);
 }

   // Write your code here
    public PerformOperation isOdd() {
     return (num) -> num % 2 != 0;
 }

 public PerformOperation isPrime() {
     return (num) -> {
         for (int i = 2; i <= num/2; i++) {
             if (num % i == 0) { return false; }
         }
         return true;
     };
 }

 public PerformOperation isPalindrome() {
    return (num) -> Integer.toString(num).equals( new StringBuilder(Integer.toString(num)).reverse().toString() );
 }
}

public class Solution {

 public static void main(String[] args) throws IOException {
  MyMath ob = new MyMath();
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  int T = Integer.parseInt(br.readLine());
  PerformOperation op;
  boolean ret = false;
  String ans = null;
  while (T--> 0) {
   String s = br.readLine().trim();
   StringTokenizer st = new StringTokenizer(s);
   int ch = Integer.parseInt(st.nextToken());
   int num = Integer.parseInt(st.nextToken());
   if (ch == 1) {
    op = ob.isOdd();
    ret = ob.checker(op, num);
    ans = (ret) ? "ODD" : "EVEN";
   } else if (ch == 2) {
    op = ob.isPrime();
    ret = ob.checker(op, num);
    ans = (ret) ? "PRIME" : "COMPOSITE";
   } else if (ch == 3) {
    op = ob.isPalindrome();
    ret = ob.checker(op, num);
    ans = (ret) ? "PALINDROME" : "NOT PALINDROME";

   }
   System.out.println(ans);
  }
 }
}

// Java Lambda Expression Hacker Rank Solution END
// MyEduWaves

Approach II: Java Lambda Expression - Solution HackerRank

// ========================
//       Information
// ========================

// Name: Java Lambda Expression HackerRank Problem
// Direct Link: https://www.hackerrank.com/challenges/java-lambda-expressions/problem
// Difficulty: Medium
// Max Score: 30
// Language: Java 8

// ========================
//         Solution Start
// ========================

// Java Lambda Expression - Hacker Rank Solution Start

import java.io.*;
import java.util.*;
interface PerformOperation {
 boolean check(int a);
}
class MyMath {
 public static boolean checker(PerformOperation p, int num) {
  return p.check(num);
 }

   // Write your code here
    public static PerformOperation isOdd() {
        return (int n) -> n % 2 != 0;
    }

    public static PerformOperation isPalindrome() {
        return (int n) -> String.valueOf(n).equals((new StringBuilder(String.valueOf(n)).reverse().toString()));
    }
    
    public static PerformOperation isPrime() {
        return (int n) -> java.math.BigInteger.valueOf(n).isProbablePrime(1);
    }
}

public class Solution {

 public static void main(String[] args) throws IOException {
  MyMath ob = new MyMath();
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  int T = Integer.parseInt(br.readLine());
  PerformOperation op;
  boolean ret = false;
  String ans = null;
  while (T--> 0) {
   String s = br.readLine().trim();
   StringTokenizer st = new StringTokenizer(s);
   int ch = Integer.parseInt(st.nextToken());
   int num = Integer.parseInt(st.nextToken());
   if (ch == 1) {
    op = ob.isOdd();
    ret = ob.checker(op, num);
    ans = (ret) ? "ODD" : "EVEN";
   } else if (ch == 2) {
    op = ob.isPrime();
    ret = ob.checker(op, num);
    ans = (ret) ? "PRIME" : "COMPOSITE";
   } else if (ch == 3) {
    op = ob.isPalindrome();
    ret = ob.checker(op, num);
    ans = (ret) ? "PALINDROME" : "NOT PALINDROME";

   }
   System.out.println(ans);
  }
 }
}

// Java Lambda Expression Hacker Rank Solution END
// MyEduWaves

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Disclaimer: The above Problem ( Java Lambda Expression ) is generated by Hackerrank but the Solution is Provided by MyEduWaves. This tutorial is only for Educational and Learning purposes. Authority if any queries regarding this post or website fill out the contact form.

I hope you have understood the solution to this HackerRank Problem. All these three solutions will pass all the test cases. Now visit Java Lambda Expression - Hackerrank Problem and try to solve it again.

All the Best!