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09.rs
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09.rs
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fn main() {
let mut comp = Computer::new(include_str!("../../input/09.txt"));
println!("Part 1: {}", comp.execute(vec![1]).unwrap());
println!("Part 2: {}", comp.execute(vec![2]).unwrap());
}
#[derive(Clone)]
struct Computer {
base: i64,
memory: Vec<i64>,
pointer: usize,
}
impl Computer {
fn new(input: &str) -> Self {
let mut mem: Vec<i64> = input
.split(',')
.map(|num| num.trim().parse().unwrap())
.collect();
mem.resize(10 * 1024, 0);
Computer {
memory: mem,
base: 0,
pointer: 0,
}
}
// parse opscode, returning the code and if the args are in position mode or imediate
// if an arg is true its in imediate mode
fn parse_opcode(&self) -> usize {
self.memory[self.pointer] as usize % 100
}
fn move_pointer(&mut self, op: usize) {
self.pointer += match op {
1..=2 | 7..=8 => 4,
3..=4 | 9 => 2,
5..=6 => 3,
_ => 0,
};
}
fn read(&mut self, mem: usize) -> &mut i64 {
let pos = self.pointer + mem;
let address = match self.memory[self.pointer] / 10i64.pow(mem as u32 + 1) % 10 {
0 => self.memory[pos] as usize,
1 => pos,
2 => (self.base + self.memory[pos]) as usize,
_ => unreachable!(),
};
&mut self.memory[address]
}
fn execute(&mut self, input: Vec<i64>) -> Option<i64> {
let mut input = input.iter();
loop {
let op = self.parse_opcode();
match op {
1 => *self.read(3) = *self.read(1) + *self.read(2),
2 => *self.read(3) = *self.read(1) * *self.read(2),
3 => *self.read(1) = *input.next().unwrap(),
4 => break Some(*self.read(1)),
5 if *self.read(1) != 0 => {
self.pointer = *self.read(2) as usize;
continue;
}
6 if *self.read(1) == 0 => {
self.pointer = *self.read(2) as usize;
continue;
}
7 => *self.read(3) = i64::from(*self.read(1) < *self.read(2)),
8 => *self.read(3) = i64::from(*self.read(1) == *self.read(2)),
9 => self.base += *self.read(1),
99 => break None,
_ => (),
}
self.move_pointer(op);
}
}
}
#[cfg(test)]
mod tests {
use super::*;
static INPUT: [&str; 3] = [
"109,1,204,-1,1001,100,1,100,1008,100,16,101,1006,101,0,99",
"1102,34915192,34915192,7,4,7,99,0",
"104,1125899906842624,99",
];
#[test]
fn test_small_input() {
let mut c0 = Computer::new(INPUT[0]);
assert_eq!(c0.execute(vec![1]).unwrap(), 109);
let mut c1 = Computer::new(INPUT[1]);
assert_eq!(c1.execute(vec![1]).unwrap().to_string().len(), 16);
let mut c2 = Computer::new(INPUT[2]);
assert_eq!(c2.execute(vec![1]).unwrap(), 1_125_899_906_842_624);
}
#[test]
fn test_large_input() {
let mut comp = Computer::new(include_str!("../../input/09.txt"));
assert_eq!(comp.execute(vec![1]).unwrap(), 3_454_977_209);
assert_eq!(comp.execute(vec![2]).unwrap(), 50120);
}
}