broken.rs

use std::io;
use std::io::prelude::*;
use std::io::BufReader;
use std::fs::File;

fn main() -> io::Result<()> {
    let f = File::open("input.txt")?;
    let reader = BufReader::new(f);

    let mut adp = Vec::<usize>::new();
    for line in reader.lines() {
        let n: usize = line?.parse().unwrap();
        adp.push(n);
    }

    adp.sort();

    let part = 1;
    if part == 0 {
        let mut last = 0;

        let mut three = 1;
        let mut one = 0;
        for i in adp {
            //if count > 0  {
            match i - last {
                1 => one += 1,
                2 => { },
                3 => three += 1,
                _ => break,
            }
            //}
            last = i;
        }

        println!("{}", one * three);
    } else {
        println!("{}", validate(adp.iter()));
    }
    Ok(())
}

fn validate<'a, T: Clone + Iterator<Item = &'a usize>>(s: T) -> usize {
    if valid(s.clone()) {
        let mut ret = 1;
            for r in s.clone() {
                ret += validate(s.clone()
                    .enumerate()
                    .filter(|&(i, _x)| i != *r)
                    .map(|(_i, x)| x));
            }
        ret
    } else {
        0
    }
}

fn valid<'a, T: Iterator<Item = &'a usize>>(s: T) -> bool {
    let mut last = 0;
    for i in s {
        if *i - last > 3 { return false; }
        last = *i;
    }
    true
}