NT/prime/sieve/linear_sieve.hpp

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Last update: 2024-05-24 22:59:46+07:00
Include: #include "NT/prime/sieve/linear_sieve.hpp"

Verified with

test/yosupo/Math/enum_prime_1.test.cpp

Code

#pragma once
template<class T>
vector<T> sieve(T n) {
    vector<bool> is_prime(n+1, true);
    vector<T> primes;

    is_prime[0] = is_prime[1] = false;

    for (T i = 2; i <= n; i++) {
        if (is_prime[i]) {
            primes.push_back(i);
        }
        for (T j = 0; j < primes.size() && i * primes[j] <= n; j++) {
            is_prime[i * primes[j]] = false;
            if (i % primes[j] == 0) {
                break;
            }
        }
    }

    return primes;
}

#line 2 "NT/prime/sieve/linear_sieve.hpp"
template<class T>
vector<T> sieve(T n) {
    vector<bool> is_prime(n+1, true);
    vector<T> primes;

    is_prime[0] = is_prime[1] = false;

    for (T i = 2; i <= n; i++) {
        if (is_prime[i]) {
            primes.push_back(i);
        }
        for (T j = 0; j < primes.size() && i * primes[j] <= n; j++) {
            is_prime[i * primes[j]] = false;
            if (i % primes[j] == 0) {
                break;
            }
        }
    }

    return primes;
}