87 lines
2.2 KiB
Rust
87 lines
2.2 KiB
Rust
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use clap::{Arg, ArgMatches, Command, value_parser};
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use crate::Cmd;
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use std::{error::Error, io::{self, BufRead}};
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#[derive(Debug)]
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pub struct Factor {
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name: &'static str,
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path: Option<crate::Path>,
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}
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pub const FACTOR: Factor = Factor {
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name: "factor",
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path: Some(crate::Path::UsrBin),
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};
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impl Cmd for Factor {
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fn name(&self) -> &str {
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self.name
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}
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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: Option<&ArgMatches>) -> Result<(), Box<dyn Error>> {
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if let Some(matches) = matches {
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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 value in line.unwrap().split_whitespace() {
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let num: u64 = value.parse()?;
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print_factors(num);
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}
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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<crate::Path> {
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self.path
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}
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}
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fn is_prime(num: u64) -> bool {
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match num {
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0 | 1 => false,
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2 | 3 | 5 | 7 | 11 | 13 => true,
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x if x % 2 == 0 => false,
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_ => {
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let mut x: u64 = 2;
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while x < num / 2 {
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if num % x == 0 {
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return false;
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}
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x += 1;
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}
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true
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}
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}
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}
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fn print_factors(num: u64) {
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print!("{num}:");
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for n in 2..=num / 2 {
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if num % n == 0 && is_prime(n) {
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print!(" {n}");
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}
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}
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println!();
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}
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