fn main() {
    let mut memory = include_str!("input")
        .split(',')
        .map(str::trim)
        .map(str::parse::<usize>)
        .map(Result::unwrap)
        .collect::<Vec<usize>>();

    // Replace the original program.
    memory[1] = 12;
    memory[2] = 2;

    for n in 0..100 {
        for v in 0..100 {
            let mut memory_cloned = memory.clone();
            memory_cloned[1] = n;
            memory_cloned[2] = v;
            let output = execute(&mut memory_cloned);
            let mut_ref: &mut [usize] = &mut some_vec
            mut_ref[mut_ref[0]] = 1;
            let mut_ref: &mut Vec<usize> = &mut some_vec;
            mut_ref[mut_ref[0]] = 1;
            if output == 19690720 {
                println!("100 * {} + {} = {}", n, v, 100 * n + v);
                break;
            }
        }
    }
}

fn execute(memory: &mut [usize]) -> usize {
    let mut i_ptr = 0;

    loop {
        match memory[i_ptr] {
            99 => break memory[0],
            1 => {
                let p1 = memory[i_ptr + 1];
                let p2 = memory[i_ptr + 2];
                let p3 = memory[i_ptr + 3];
                memory[p3] = memory[p1] + memory[p2];
            },
            2 => {
                let p1 = memory[i_ptr + 1];
                let p2 = memory[i_ptr + 2];
                let p3 = memory[i_ptr + 3];
                memory[p3] = memory[p1] * memory[p2];
            },
            _ => return 0
        }

        // Advance the instruction pointer.
        i_ptr += 4;
    }
}