#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unused_mut)]
use std::env;
use std::fs::File;
use std::io::Read;

fn rec(val: i64, acc: i64, mut eq: Vec<i64>) -> bool {
    if eq.len() == 0 {
        if val == acc {
            return true;
        } else {
            return false;
        }
    }

    let a = eq.pop().unwrap();
    return rec(val, acc * a, eq.clone()) || rec(val, acc + a, eq.clone());
}

fn rec2(val: i64, acc: i64, mut eq: Vec<i64>) -> bool {
    if eq.len() == 0 {
        if val == acc {
            return true;
        } else {
            return false;
        }
    }

    let a = eq.pop().unwrap();
    return rec2(val, a + acc * 10_i64.pow(a.checked_ilog10().unwrap() + 1), eq.clone())
        || rec2(val, acc * a, eq.clone())
        || rec2(val, acc + a, eq.clone());
}

fn main() {
    let args: Vec<String> = env::args().collect();
    let filename = if args.len() == 1 {
        "in/".to_owned() + args[0].split('/').last().unwrap() + ".pzl"
    } else {
        args[1].clone()
    };
    let mut f = File::open(filename).expect("cannot open file");
    let mut content = String::new();
    f.read_to_string(&mut content).expect("cannot read file");
    let lines = content.trim_end().split("\n");

    let mut vals: Vec<i64> = Vec::new();
    let mut eqs: Vec<Vec<i64>> = Vec::new();
    for line in lines {
        let (c, rest) = line.split_once(": ").unwrap();
        vals.push(c.parse().unwrap());
        eqs.push(
            rest.split(" ")
                .map(|a| a.parse().unwrap())
                .collect::<Vec<i64>>()
                .into_iter()
                .rev()
                .collect(),
        );
    }

    let mut res1 = 0;
    let mut res2 = 0;
    for i in 0..eqs.len() {
        if rec(vals[i], 0, eqs[i].clone()) {
            res1 += vals[i];
        }
        if rec2(vals[i], 0, eqs[i].clone()) {
            res2 += vals[i];
        }
    }

    println!("res1: {}", res1);
    println!("res2: {}", res2);
    assert_eq!(res1, 66343330034722);
    assert_eq!(res2, 637696070419031);
}