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Sieve of Eratosthenes with C++ constexpr
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#include <stdio.h> | |
template <size_t N> | |
struct PrimeTable { | |
constexpr PrimeTable() : sieve() { | |
sieve[0] = sieve[1] = false; | |
for (size_t i = 2; i < N; i++) sieve[i] = true; | |
for (size_t i = 2; i < N; i++) { | |
if (sieve[i]) | |
for (size_t j = i*i; j < N; j += i) sieve[j] = false; | |
} | |
} | |
bool sieve[N]; | |
}; | |
int main() { | |
constexpr auto table = PrimeTable<100000>(); | |
for (int i = 0; i < 20; i++) { | |
printf("isPrime(%d): %d\n", i, table.sieve[i]); | |
} | |
return 0; | |
} |
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