OSS Sync, cl 163329677

This commit is contained in:
misterg 2018-01-02 14:42:09 -05:00
parent 1c2f190704
commit e7734fb80c

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@ -103,11 +103,15 @@ class PreCalculatedPrimeTable : public PrimeTable {
::std::fill(is_prime_, is_prime_ + is_prime_size_, true); ::std::fill(is_prime_, is_prime_ + is_prime_size_, true);
is_prime_[0] = is_prime_[1] = false; is_prime_[0] = is_prime_[1] = false;
for (int i = 2; i <= max; i++) { // Checks every candidate for prime number (we know that 2 is the only even
// prime).
for (int i = 2; i*i <= max; i += i%2+1) {
if (!is_prime_[i]) continue; if (!is_prime_[i]) continue;
// Marks all multiples of i (except i itself) as non-prime. // Marks all multiples of i (except i itself) as non-prime.
for (int j = 2*i; j <= max; j += i) { // We are starting here from i-th multiplier, because all smaller
// complex numbers were already marked.
for (int j = i*i; j <= max; j += i) {
is_prime_[j] = false; is_prime_[j] = false;
} }
} }