use std::env::args;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;

fn step(levels: &mut Vec<u8>, rows: usize, cols: usize) -> u32 {
    for y in 0..rows {
        for x in 0..cols {
            levels[y * cols + x] += 1;
        }
    }

    let mut flashes = 0;
    let mut flashed = true;
    while flashed {
        flashed = false;
        for y in 0..rows {
            for x in 0..cols {
                let i = y * cols + x;
                if levels[i] > 9 {
                    flashed = true;
                    flashes += 1;
                    levels[i] = 0;

                    if x != 0 && y != 0 && levels[i - cols - 1] != 0 {
                        levels[i - cols - 1] += 1;
                    }
                    if y != 0 && levels[i - cols] != 0 {
                        levels[i - cols] += 1;
                    }
                    if x != cols - 1 && y != 0 && levels[i - cols + 1] != 0 {
                        levels[i - cols + 1] += 1;
                    }
                    if x != cols - 1 && levels[i + 1] != 0 {
                        levels[i + 1] += 1;
                    }
                    if x != cols - 1 && y != rows - 1 && levels[i + cols + 1] != 0 {
                        levels[i + cols + 1] += 1;
                    }
                    if y != rows - 1 && levels[i + cols] != 0 {
                        levels[i + cols] += 1;
                    }
                    if x != 0 && y != rows - 1 && levels[i + cols - 1] != 0 {
                        levels[i + cols - 1] += 1;
                    }
                    if x != 0 && levels[i - 1] != 0 {
                        levels[i - 1] += 1;
                    }
                }
            }
        }
    }
    return flashes;
}

fn main() {
    let path = args().nth(1).unwrap();
    let file = File::open(path).unwrap();

    let mut rows = 0;
    let mut cols = 0;
    let mut levels = vec![];

    for line in BufReader::new(file).lines() {
        let l = line.unwrap();
        rows += 1;
        cols = l.len();
        for c in l.chars() {
            levels.push(c.to_digit(10).unwrap() as u8);
        }
    }

    let mut flashes = 0;
    for _ in 0..100 {
        flashes += step(&mut levels, rows, cols);
    }

    print!("{}\n", flashes);
}