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#![allow(dead_code)]
use std::fs;
fn read_file(file : &str) -> String {
fs::read_to_string(file).unwrap()
}
fn required_fuel(mass : u32) -> u32 {
(mass / 3).saturating_sub(2)
}
fn required_fuel_with_fuel(mass : u32) -> u32 {
let mut total = 0;
let mut current = mass;
loop {
current = required_fuel(current);
total += current;
if current == 0 {
break;
}
}
total
}
fn day1() {
let input = read_file("input1");
let sum : u32 = input.split('\n')
.filter(|x| !x.is_empty())
.map(|x| x.parse::<u32>().unwrap())
.map(|x| required_fuel(x))
.sum();
println!("1a: {}", sum);
let sum2 : u32 = input.split('\n')
.filter(|x| !x.is_empty())
.map(|x| x.parse::<u32>().unwrap())
.map(|x| required_fuel_with_fuel(x))
.sum();
println!("1b: {}", sum2);
}
fn run_program(input : Vec<usize>) -> Vec<usize> {
let mut mem = input.clone();
for i in 0..mem.len()/4 {
let pos = i * 4;
let opcode = mem[pos];
if opcode == 99 {
break;
}
let op1 = mem[pos+1];
let op2 = mem[pos+2];
let op3 = mem[pos+3];
match opcode {
1 => { mem[op3] = mem[op1] + mem[op2]; }
2 => { mem[op3] = mem[op1] * mem[op2]; }
_ => panic!("invalid opcode")
}
}
mem
}
fn day2() {
let mut input = read_file("input2");
input.pop();
let mut program : Vec<usize> = input.split(',')
.map(|x| x.parse::<usize>().unwrap())
.collect();
program[1] = 12;
program[2] = 2;
let mem = run_program(program.clone());
println!("2a: {}", mem[0]);
for noun in 0..99 {
for verb in 0..99 {
program[1] = noun;
program[2] = verb;
let mem = run_program(program.clone());
if mem[0] == 19690720 {
println!("2b: {}", 100 * noun + verb);
return;
}
}
}
}
fn main() {
day2();
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_day1() {
assert_eq!(required_fuel(12), 2);
assert_eq!(required_fuel(14), 2);
assert_eq!(required_fuel(1969), 654);
assert_eq!(required_fuel(100756), 33583);
assert_eq!(required_fuel_with_fuel(14), 2);
assert_eq!(required_fuel_with_fuel(1969), 966);
assert_eq!(required_fuel_with_fuel(100756), 50346);
}
#[test]
fn test_day2() {
assert_eq!(run_program(vec!(1,0,0,0,99)), vec!(2,0,0,0,99));
assert_eq!(run_program(vec!(2,3,0,3,99)), vec!(2,3,0,6,99));
assert_eq!(run_program(vec!(2,4,4,5,99,0)), vec!(2,4,4,5,99,9801));
assert_eq!(run_program(vec!(1,1,1,4,99,5,6,0,99)), vec!(30,1,1,4,2,5,6,0,99));
}
}
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