AOC 2023 Day 6

use std::env;
use std::io::{self, prelude::*};
use std::fs::File;

fn solve(input: &str) -> io::Result<()> {
    // File handling
    let input_str = std::fs::read_to_string(input).unwrap();
    let input_str = input_str.trim();
    let input: Vec<_> = input_str.lines().collect();

    // Part 1 Inputs
    let times: Vec<_> = input[0]
        .split_whitespace()
        .skip(1)
        .map(|x| x.parse::<usize>().unwrap())
        .collect();
    let distances: Vec<_> = input[1]
        .split_whitespace()
        .skip(1)
        .map(|x| x.parse::<usize>().unwrap())
        .collect();

    // Part 1
    let mut part1 = 1;
    for (time,dist) in times.iter().zip(distances.iter()) {
        let ways = (1..*time)
            .into_iter()
            .filter(|hold| hold * (time - hold) > *dist)
            .count();
        if ways > 0 { part1 *= ways; }
    }
    println!("Part 1: {part1}"); // 800280

    // Part 2 Inputs
    let time_p2 = times
        .iter()
        .map(|x| format!("{x}"))
        .collect::<Vec<_>>()
        .concat()
        .parse::<usize>()
        .unwrap();
    let dist_p2 = distances
        .iter()
        .map(|x| format!("{x}"))
        .collect::<Vec<_>>()
        .concat()
        .parse::<usize>()
        .unwrap();

    // Part 2 Solve
    let part2 = (1..time_p2)
        .into_iter()
        .filter(|hold| hold * (time_p2 - hold) > dist_p2)
        .count();
    println!("Part 2: {part2}"); // 45128024

    Ok(())
}

fn main() {
    let args: Vec<String> = env::args().collect();
    let filename = &args[1];
    solve(&filename).unwrap();
}