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sieve.rs
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sieve.rs
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use quickcheck::quickcheck;
fn sieve(n: usize) -> Vec<usize> {
if n <= 1 {
return vec![];
}
let mut marked = vec![false; n + 1];
marked[0] = true;
marked[1] = true;
marked[2] = true;
for p in 2..n {
for i in (2 * p..n).filter(|&n| n % p == 0) {
marked[i] = true;
}
}
marked
.iter()
.enumerate()
.filter_map(|(i, &m)| if m { None } else { Some(i) })
.collect()
}
fn is_prime(n: usize) -> bool {
n != 0 && n != 1 && (2..).take_while(|i| i * i <= n).all(|i| n % i != 0)
}
fn main() {
fn prop_all_prime(n: usize) -> bool {
sieve(n).into_iter().all(is_prime)
}
fn prop_prime_iff_in_the_sieve(n: usize) -> bool {
sieve(n) == (0..(n + 1)).filter(|&i| is_prime(i)).collect::<Vec<_>>()
}
quickcheck(prop_all_prime as fn(usize) -> bool);
quickcheck(prop_prime_iff_in_the_sieve as fn(usize) -> bool);
}