intcode.rs

use std::io::BufRead;
fn main() {
    let reader = std::io::BufReader::new(std::fs::File::open(std::env::args().nth(1).unwrap()).unwrap());
    let mut input = String::new();
    for line in reader.lines() {
        for ch in line.unwrap().chars() {
            match ch {
                '#' => break,
                ' ' | '\t' | '\r' | '\n' => (),
                c => input.push(c),
            }
        }
    }
    run(&input, std::env::var_os("DEBUG").is_some());
}

pub fn run(input: &str, debug: bool) {
    let mut nums = input.trim().split(",").map(|x| x.parse::<isize>().unwrap()).collect::<Vec<_>>();
    let mut ci = 0;
    loop {
        if debug {
            println!("pc = {}", ci);
            println!("{:?}", &nums[ci..nums.len().min(ci+4)]);
            println!("{:?}", nums[ci+1..nums.len().min(ci+4)].iter().map(|n| nums.get(*n as usize)).collect::<Vec<_>>());
            println!();
        }
        match nums[ci] % 100 {
            1 => {
                let mut a = nums[ci+1];
                let mut b = nums[ci+2];
                let c = nums[ci+3];

                let m = nums[ci] / 100 % 10;
                let n = nums[ci] / 1000 % 10;

                if m == 0 { a = nums[a as usize]; }
                if n == 0 { b = nums[b as usize]; }

                nums[c as usize] = a + b;
                ci+=4;
            }
            2 => {
                let mut a = nums[ci+1];
                let mut b = nums[ci+2];
                let c = nums[ci+3];

                let m = nums[ci] / 100 % 10;
                let n = nums[ci] / 1000 % 10;

                if m == 0 { a = nums[a as usize]; }
                if n == 0 { b = nums[b as usize]; }

                nums[c as usize] = a * b;
                ci+=4;
            }
            3 => {
                let a = nums[ci+1];
                let mut input = String::new();
                std::io::stdin().read_line(&mut input).unwrap();
                nums[a as usize] = input.trim().parse().unwrap();
                ci += 2;
            }
            4 => {
                let mut a = nums[ci+1];
                let m = nums[ci] / 100 % 10;
                if m == 0 { a = nums[a as usize]; }
                println!("{}", a);
                ci += 2;
            }

            5 => {
                let mut a = nums[ci+1];
                let mut b = nums[ci+2];

                let m = nums[ci] / 100 % 10;
                let n = nums[ci] / 1000 % 10;

                if m == 0 { a = nums[a as usize]; }
                if n == 0 { b = nums[b as usize]; }
                if a != 0 {
                    ci = b as usize;
                } else {
                    ci += 3;
                }
            }
            6 => {
                let mut a = nums[ci+1];
                let mut b = nums[ci+2];

                let m = nums[ci] / 100 % 10;
                let n = nums[ci] / 1000 % 10;

                if m == 0 { a = nums[a as usize]; }
                if n == 0 { b = nums[b as usize]; }
                if a == 0 {
                    ci = b as usize;
                } else {
                    ci += 3;
                }
            }
            7 => {
                let mut a = nums[ci+1];
                let mut b = nums[ci+2];
                let c = nums[ci+3];

                let m = nums[ci] / 100 % 10;
                let n = nums[ci] / 1000 % 10;

                if m == 0 { a = nums[a as usize]; }
                if n == 0 { b = nums[b as usize]; }
                if a < b {
                    nums[c as usize] = 1;
                } else {
                    nums[c as usize] = 0;
                }

                ci += 4;
            }
            8 => {
                let mut a = nums[ci+1];
                let mut b = nums[ci+2];
                let c = nums[ci+3];

                let m = nums[ci] / 100 % 10;
                let n = nums[ci] / 1000 % 10;

                if m == 0 { a = nums[a as usize]; }
                if n == 0 { b = nums[b as usize]; }
                if a == b {
                    nums[c as usize] = 1;
                } else {
                    nums[c as usize] = 0;
                }

                ci += 4;
            }
            99 => break,
            _ => panic!("Bad opcode"),
        }
    }
}