49 lines
1.1 KiB
C++
49 lines
1.1 KiB
C++
// This solution needs the GNU MP Bignum library
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// g++ euler10.cpp -o euler10 -lgmpxx -lgmp
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#include <gmpxx.h>
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#include <cmath>
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#include <vector>
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#include <iostream>
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void sieve(std::vector<int>& primes, int const limit) {
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if (limit < 2) {
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return;
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} else if (limit < 3) {
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primes.push_back(2);
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return;
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}
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primes.push_back(2);
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primes.push_back(3);
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for (int num = 5; num <= limit; num += 2) {
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int sqrtnum = (int) std::sqrt(num);
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bool isPrime = true;
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for (auto primeIt = ++primes.begin(); primeIt != primes.end() && *primeIt <= sqrtnum; ++primeIt) {
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if (num % *primeIt == 0) {
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isPrime = false;
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break;
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}
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}
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if (isPrime) {
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primes.push_back(num);
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}
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}
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}
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int main(void) {
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constexpr int limit = 2000000;
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constexpr int PRIMELIMIT = limit - 1;
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std::vector<int> primes;
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sieve(primes, PRIMELIMIT);
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mpz_class sum = 0;
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for (auto primeIt = primes.begin(); primeIt != primes.end(); ++primeIt) {
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sum += *primeIt;
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}
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std::cout << sum << std::endl;
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return EXIT_SUCCESS;
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}
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