use aoc_runner_derive::{aoc, aoc_generator};

#[aoc_generator(day9)]
pub fn input_generator(input: &str) -> Vec<usize> {
    input
        .lines()
        .map(|l| l.trim().parse())
        .collect::<Result<Vec<usize>, _>>()
        .unwrap()
}

#[aoc(day9, part1)]
pub fn solve_part1(input: &Vec<usize>) -> usize {
    for (n, win) in input.as_slice().windows(25).enumerate() {
        let n = n + 25;
        if n >= input.len() {
            continue;
        }
        let c = input[n];
        let mut valid = false;
        for (i1, n1) in win.iter().enumerate() {
            for (i2, n2) in win.iter().enumerate() {
                if i1 == i2 {
                    continue;
                }
                if n1 + n2 == c {
                    valid = true;
                }
            }
        }
        if !valid {
            return c;
        }
    }
    panic!("No match found!");
}

#[aoc(day9, part2)]
pub fn solve_part2(input: &Vec<usize>) -> usize {
    let inv_num = solve_part1(input);
    for start in 0..input.len() {
        for length in 2..(input.len() - start) {
            let s: Vec<usize> = input.iter().skip(start).take(length).cloned().collect();
            if s.iter().sum::<usize>() == inv_num {
                return s.iter().max().unwrap() + s.iter().min().unwrap();
            }
        }
    }
    panic!("No match found!");
}