The Prime 41 (2)

ThePrime41_2.cpp

#include <iostream>
#include <type_traits>

using namespace std;

const int Max = 1000;
bool isPrime[Max];
int primes[Max] = { 0 };
int primeCount = 0;

int minIndex = 0;
int maxIndex = 0;
int maxSum = 2;

void FillPrimes()
{
	isPrime[0] = false;
	isPrime[1] = false;
	for (int i = 2; i < Max; i++)
	{
		isPrime[i] = true;
	}

	for (int i = 2; i < Max; i++)
	{
		if (isPrime[i])
		{
			for (int j = i * 2; j < Max; j += i)
			{
				isPrime[j] = false;
			}
		}
	}

	for (int i = 2; i < Max; i++)
	{
		if (isPrime[i])
		{
			primes[primeCount++] = i;
		}
	}
}

void PrintResult()
{
	for (int i = minIndex; i < maxIndex; i++)
	{
		cout << primes[i] << " + ";
	}
	cout << primes[maxIndex] << " = " << maxSum << endl;
}

int main()
{
	FillPrimes();

	int start = 0;
	int sum = 2;
	for (int i = 1; i < primeCount; i++)
	{
		int newSum = sum + primes[i];
		if (newSum >= Max)
		{
			i--;
			sum -= primes[start++];
		}
		else
		{
			sum = newSum;
		}

		if (isPrime[sum])
		{
			int d1 = i - start;
			int d2 = maxIndex - minIndex;
			if ((d1 > d2) || (d1 == d2 && sum > maxSum))
			{
				maxSum = sum;
				minIndex = start;
				maxIndex = i;
				PrintResult();
			}
		}
	}

	PrintResult();

	return 0;
}