44 lines
903 B
Rust
44 lines
903 B
Rust
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use std::io::Write;
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use std::str::FromStr;
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fn gcd(mut n: u64, mut m: u64) -> u64 {
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assert!(n != 0 && m != 0);
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while m != 0 {
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if m < n {
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let t = m;
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m = n;
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n = t;
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}
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m = m % n;
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}
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n
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}
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#[test]
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fn test_gcd() {
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assert_eq!(gcd(14, 15), 1);
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assert_eq!(gcd(2 * 3 * 5 * 11 * 17,
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3 * 7 * 11 * 13 * 19),
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3 * 11);
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}
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fn main() {
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let mut numbers = Vec::new();
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for arg in std::env::args().skip(1) {
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numbers.push(u64::from_str(&arg).expect("error parsing argument as u64"));
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}
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if numbers.len() == 0 {
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writeln!(std::io::stderr(), "Usage: gcd NUMBER...").unwrap();
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std::process::exit(1);
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}
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let mut d = numbers[0];
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for m in &numbers[1..] {
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d = gcd(d, *m);
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}
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println!("The greatest common divisor of {:?} is {}", numbers, d);
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}
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