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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,47 +1,47 @@ | ||
| pub fn sieve(n: usize) -> Vec<u64> { | ||
| let mut res: Vec<u64> = vec![]; | ||
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| if n < 2 { | ||
| return res; | ||
| } | ||
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| let mut is_prime = vec![true; n + 1]; | ||
| is_prime[0] = false; | ||
| is_prime[1] = false; | ||
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| res.push(2); | ||
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| // Mark all even numbers as non-prime except 2 | ||
| for i in (4..n).step_by(2) { | ||
| is_prime[i] = false; | ||
| } | ||
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| let mut i = 3; | ||
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| // If the number is prime, the next multiple that is not prime is its square | ||
| while i * i <= n { | ||
| if is_prime[i] { | ||
| res.push(i as u64); | ||
| // Except 2 all other primes are odd | ||
| // So we can skip even multiples | ||
| for j in (i * i..n).step_by(2 * i) { | ||
| is_prime[j] = false; | ||
| } | ||
| } | ||
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| i += 2; | ||
| } | ||
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| res | ||
| } | ||
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| #[cfg(test)] | ||
| mod test { | ||
| use super::sieve; | ||
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| #[test] | ||
| fn test_sieve() { | ||
| let result = sieve(10); | ||
| assert_eq!(result, vec![2, 3, 5, 7]); | ||
| } | ||
| } | ||
| // pub fn sieve(n: usize) -> Vec<u64> { | ||
| // let mut res: Vec<u64> = vec![]; | ||
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| // if n < 2 { | ||
| // return res; | ||
| // } | ||
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| // let mut is_prime = vec![true; n + 1]; | ||
| // is_prime[0] = false; | ||
| // is_prime[1] = false; | ||
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| // res.push(2); | ||
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| // // Mark all even numbers as non-prime except 2 | ||
| // for i in (4..n).step_by(2) { | ||
| // is_prime[i] = false; | ||
| // } | ||
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| // let mut i = 3; | ||
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| // // If the number is prime, the next multiple that is not prime is its square | ||
| // while i * i <= n { | ||
| // if is_prime[i] { | ||
| // res.push(i as u64); | ||
| // // Except 2 all other primes are odd | ||
| // // So we can skip even multiples | ||
| // for j in (i * i..n).step_by(2 * i) { | ||
| // is_prime[j] = false; | ||
| // } | ||
| // } | ||
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| // i += 2; | ||
| // } | ||
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| // res | ||
| // } | ||
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| // #[cfg(test)] | ||
| // mod test { | ||
| // use super::sieve; | ||
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| // #[test] | ||
| // fn test_sieve() { | ||
| // let result = sieve(10); | ||
| // assert_eq!(result, vec![2, 3, 5, 7]); | ||
| // } | ||
| // } |