pub fn f(input: Vec<Vec<char>>) -> u64 {
    for x in 1..input[0].len() {
        let mut cnt: u32 = 0;

        for i in 0..input.len() {
            for j in 0..x {
                if 2 * x - 1 - j >= input[0].len() {
                    continue;
                }
                if input[i][j] != input[i][2 * x - 1 - j] {
                    cnt += 1;
                }
            }
        }

        if cnt == 1 {
            return x as u64;
        }
    }

    for y in 1..input.len() {
        let mut cnt: u32 = 0;

        for i in 0..y {
            for j in 0..input[i].len() {
                if 2 * y - 1 - i >= input.len() {
                    continue;
                }
                if input[i][j] != input[2 * y - 1 - i][j] {
                    cnt += 1;
                }
            }
        }

        if cnt == 1 {
            return (y * 100) as u64;
        }
    }

    panic!();
}

pub fn main() {
    let txt = std::fs::read_to_string("./input/day13.txt").unwrap();
    let input = txt
        .split("\n\n")
        .map(|s| {
            s.lines()
                .map(|s| s.chars().collect::<Vec<char>>())
                .collect::<Vec<_>>()
        })
        .collect::<Vec<_>>();

    let mut sum: u64 = 0;
    for i in input {
        sum += f(i);
    }

    println!("{}", sum);
}