Task and Solution : Project Euler #3: Largest prime factor (HackerRank)

 This problem is a programming version of Problem 3 from projecteuler.net

The prime factors of  are  and .

What is the largest prime factor of a given number ?

Input Format

First line contains , the number of test cases. This is followed by  lines each containing an integer .

Constraints

Output Format

For each test case, display the largest prime factor of .

Sample Input 0

2
10
17

Sample Output 0

5
17

Explanation 0

• Prime factors of  are , largest is .
• Prime factor of  is  itself, hence largest is .

Solution

/*

 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license

 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template

 */

package hackerrank.contest.projecteuler;

import java.io.*;

import java.math.*;

import java.security.*;

import java.text.*;

import java.util.*;

import java.util.concurrent.*;

import java.util.function.*;

import java.util.regex.*;

import java.util.stream.*;

import static java.util.stream.Collectors.joining;

import static java.util.stream.Collectors.toList;

/**

 *

 * @author surachman

 */

public class Largest_prime_factor1 {

    public static void main(String[] args) {

      Scanner in = new Scanner(System.in);

      int t = in.nextInt();

      long max=0;

      for(int a0 = 0; a0 < t; a0++){

          long n = in.nextLong();

          long div = 2;

          while (div <= Math.floor(Math.sqrt(n))) {

            if (n % div== 0) {

              n /= div;

            } else {

              div++;

            }

          }

         System.out.println(n);

        }

    }

   

}

Source : HackerRank

Task and Solution : ProjectEuler+Project Euler #2: Even Fibonacci numbers in Java (HackerRank)

 

This problem is a programming version of Problem 2 from projecteuler.net

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with  and , the first  terms will be:

By considering the terms in the Fibonacci sequence whose values do not exceed , find the sum of the even-valued terms.

Input Format

First line contains  that denotes the number of test cases. This is followed by  lines, each containing an integer, .

Constraints

Output Format

Print the required answer for each test case.

Sample Input 0

2
10
100

Sample Output 0

10
44

Explanation 0

• For , we have , sum is .
• For , we have , sum is .

Solution

/*

 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license

 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template

 */

package hackerrank.contest.projecteuler;

import java.io.*;

import java.math.*;

import java.security.*;

import java.text.*;

import java.util.*;

import java.util.concurrent.*;

import java.util.function.*;

import java.util.regex.*;

import java.util.stream.*;

import static java.util.stream.Collectors.joining;

import static java.util.stream.Collectors.toList;

/**

 *

 * @author surachman

 */

public class Even_Fibonacci_numbers_1 {

    public static void main(String args[]){

        Scanner sc = new Scanner(System.in);

        int t = sc.nextInt();

        for(int i = 0; i < t; i++){

            long n = sc.nextLong();

            long a = 0;

            long b = 2;

            long ans = b;

           

            while(4*b + a <= n){

                ans += 4*b + a;

                long temp = a;

                a = b;

                b = 4*b + temp;

            }

            System.out.println(ans);

        }

    }

}

Source : HackerRank