Hackerrank - Project Euler+ #006 - Sum square difference

Hackerrank – Problem description

The problem description – Hackerrank.

Solution

We calculate 3 equations for every number from 1 to N.

Sum of squares:

$1^2 + 2^2 + 3^3 + \cdots + {(n-1)}^2 + n^2 = S_1$

Square of sum:

${(1+2+3 + \cdots + (n-1) + n)}^2 = S_2$

Result – Difference between sums:

$d = \| S_1 - S_2 \|$

I created solution in:

Java

All solutions are also available on my GitHub profile.

Java

import java.util.Scanner;

public class SumSquareDifference
{
	public static void main(String[] args)
	{
		Scanner scanner = new Scanner(System.in);
		int tests = Integer.parseInt(scanner.nextLine());
		for (int i = 0; i < tests; i++)
		{
			int number = Integer.parseInt(scanner.nextLine());
			System.out.println(sumDifference(number));
		}
		scanner.close();
	}

	private static long sumDifference(int number)
	{
		long squareSum = 0;
		long sumSqares = 0;
		for (int i = 1; i <= number; i++)
		{
			squareSum += i;
			sumSqares += (i * i);
		}
		squareSum *= squareSum;

		return squareSum - sumSqares;
	}
}

import java.util.Scanner;

public class SumSquareDifference

{

public static void main(String[] args)

{

Scanner scanner = new Scanner(System.in);

int tests = Integer.parseInt(scanner.nextLine());

for (int i = 0; i < tests; i++)

{

int number = Integer.parseInt(scanner.nextLine());

System.out.println(sumDifference(number));

}

scanner.close();

}

private static long sumDifference(int number)

{

long squareSum = 0;

long sumSqares = 0;

for (int i = 1; i <= number; i++)

{

squareSum += i;

sumSqares += (i * i);

}

squareSum *= squareSum;

return squareSum - sumSqares;

}

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Project Euler+ #006 – Sum square difference

Hackerrank – Problem description

Solution

Java

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