ex1.rs

// check if any greater than 9, set them to -1
// and increase neighboring and diagonal numbers
for i in 0..input.len() {
    for j in 0..input[i].len() {
        if input[i][j] > 9 {
            input[i][j] = -1;
            if i > 0 {
                input[i - 1][j] += 1;
            }
            if i < input.len() - 1 {
                input[i + 1][j] += 1;
            }
            if j > 0 {
                input[i][j - 1] += 1;
            }
            if j < input[i].len() - 1 {
                input[i][j + 1] += 1;
            }
            if i > 0 && j > 0 {
                input[i - 1][j - 1] += 1;
            }
            if i > 0 && j < input[i].len() - 1 {
                input[i - 1][j + 1] += 1;
            }
            if i < input.len() - 1 && j > 0 {
                input[i + 1][j - 1] += 1;
            }
            if i < input.len() - 1 && j < input[i].len() - 1 {
                input[i + 1][j + 1] += 1;
            }
        }
    }
}