Java Lambda Expressions – Hacker Rank Solution

Java Lambda Expressions  - Hacker Rank Solution
Java Lambda Expressions – Hacker Rank Solution


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  lines of output.

Sample Input

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

The  subsequent lines each describe a test case in the form of  space-separated integers:
The first integer specifies the condition to check for ( for Odd/Even,  for Prime, or  for Palindrome). The second integer denotes the number to be checked.

1 4
2 5
3 898
1 3
2 12

Sample Output


Java Lambda Expressions – Hacker Rank Solution

import java.util.*;
interface PerformOperation {
 boolean check(int a);
class MyMath {
 public static boolean checker(PerformOperation p, int num) {
  return p.check(num);
   PerformOperation isOdd()
       PerformOperation po = (int a)-> a%2 == 0 ? false : true;
       return po;
   PerformOperation isPrime()
       PerformOperation po = (int a)->
           if(a == 1) return true;
               for (int i =  2; i < Math.sqrt(a); i++)
                    if(a%i == 0) return false;
                return true;
       return po;
   PerformOperation isPalindrome()
       ArrayList<Integer> aa = new ArrayList<>();
       PerformOperation po = (int a)->
            String str = Integer.toString(a);
           String reverse = "";
           for(int i = str.length()-1; i >= 0; i--)
               reverse = reverse + str.charAt(i);
           if(reverse.equals(str)) return true;
           return false;
       return po;
public class Solution {
 public static void main(String[] args) throws IOException {
  MyMath ob = new MyMath();
  BufferedReader br = new BufferedReader(new InputStreamReader(;
  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";

Disclaimer: The above Problem (Java Lambda Expressions ) is generated by Hackerrank but the Solution is Provided by Chase2Learn. This tutorial is only for Educational and Learning purposes. Authority if any of the queries regarding this post or website fill the following contact form thank you.

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