73 lines
1.7 KiB
Rust
73 lines
1.7 KiB
Rust
use super::Cmd;
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use clap::{value_parser, Arg, ArgMatches, Command};
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use std::{
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error::Error,
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io::{self, BufRead},
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};
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#[derive(Debug)]
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pub struct Factor;
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impl Cmd for Factor {
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fn cli(&self) -> Command {
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Command::new("factor")
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.about("factor numbers")
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.after_help(
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"Print the prime factors of each specified integer NUMBER. If none are\n\
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specified on the command line, read them from standard input.",
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)
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.arg(
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Arg::new("number")
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.help("the numbers to factor")
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.num_args(0..)
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.value_parser(value_parser!(u64)),
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)
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}
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fn run(&self, matches: &ArgMatches) -> Result<(), Box<dyn Error>> {
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match matches.get_many::<u64>("number") {
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Some(numbers) => {
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numbers.for_each(|n| print_factors(*n));
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}
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None => {
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for line in io::stdin().lock().lines() {
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for num in line?.split_whitespace() {
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print_factors(num.parse()?);
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}
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}
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}
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}
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Ok(())
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}
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fn path(&self) -> Option<shitbox::Path> {
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Some(shitbox::Path::UsrBin)
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}
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}
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fn first_factor(num: u64) -> u64 {
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if num % 2 == 0 {
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return 2;
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}
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for n in (3..=num).step_by(1) {
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if num % n == 0 {
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return n;
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}
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}
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num
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}
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fn print_factors(num: u64) {
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print!("{num}:");
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let mut n = num;
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loop {
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let f = first_factor(n);
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print!(" {f}");
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if f == n {
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break;
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}
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n /= f;
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}
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println!();
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}
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