70 lines
1.7 KiB
Rust
70 lines
1.7 KiB
Rust
// rustc -O -o primes_rs primes.rs; ./primes_rs
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use std::env;
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use std::time::{Instant, Duration};
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const PRIMES_COUNT: u32 = 10000000;
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fn get_primes7(count: u32) -> Vec<u32> {
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if count < 2 {
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return vec![];
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} else if count == 2 {
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return vec![2];
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}
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let mut s = Vec::new();
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let mut i = 3;
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while i < count+1 {
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s.push(i);
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i += 2;
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}
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let mroot = (count as f32).sqrt() as u32;
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let half = s.len() as u32;
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let mut i: u32 = 0;
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let mut m: u32 = 3;
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while m <= mroot {
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if s.get(i as usize).is_some() && s[i as usize] != 0 {
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let mut j = (m*m-3)/2;
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s[j as usize] = 0;
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while j < half {
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s[j as usize] = 0;
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j += m;
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}
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}
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i += 1;
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m = 2*i+3;
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}
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let mut res = Vec::new();
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res.push(2);
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res.extend(s.into_iter().filter(|x| *x != 0));
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res
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}
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fn main() {
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let run_time_secs = match env::var("RUN_TIME") {
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Ok(v) => match v.parse::<u32>() {
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Ok(i) => i,
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Err(err) => panic!("RUN_TIME environment variable error: {}", err),
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},
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Err(_err) => 5,
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};
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let run_time = Duration::new(run_time_secs as u64, 0);
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let start = Instant::now();
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let mut iterations = 3;
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while start.elapsed() < run_time || iterations < 3 {
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let primes = get_primes7(PRIMES_COUNT);
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println!("Found {} prime numbers.", primes.len());
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iterations += 1;
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}
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let dur = start.elapsed();
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let result_time = dur.as_secs() as f64 + (dur.subsec_millis() as f64) / 1000.0;
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println!("Rust: {} iterations in {:.2} sec = {:.2} sec per 30 iterations",
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iterations, result_time, result_time / (iterations as f64) * 30.0);
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}
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