150 lines
4.2 KiB
Rust
150 lines
4.2 KiB
Rust
pub fn process_part1(input: &str) -> i32 {
|
|
input
|
|
.lines()
|
|
.map(extract_mul_pairs)
|
|
.map(|pairs| pairs.iter().map(|(a, b)| a * b).sum::<i32>())
|
|
.sum()
|
|
}
|
|
|
|
// Could use this regex but wouldn't know how to solve part 2
|
|
// /mul\([0-9]{1,3},[0-9]{1,3}\)/g
|
|
// /don't\(\).*do\(\)/g would select anything between don't() and do()
|
|
// not sure how to invert this and combine
|
|
fn extract_mul_pairs(line: &str) -> Vec<(i32, i32)> {
|
|
let mut pairs = Vec::new();
|
|
for (idx, _) in line.match_indices("mul(") {
|
|
let mut invalid = false;
|
|
let mut comma_pos = 0;
|
|
let mut pair = ("".to_string(), "".to_string());
|
|
// max length of parenthesis == 9
|
|
for paren_idx in 0..9 {
|
|
let paren_content = match line.as_bytes().get(idx + 4 + paren_idx) {
|
|
Some(content) => *content as char,
|
|
None => {
|
|
invalid = true;
|
|
break;
|
|
}
|
|
};
|
|
if paren_content == ')' {
|
|
if comma_pos == 0 {
|
|
invalid = true;
|
|
}
|
|
break;
|
|
}
|
|
if paren_content == ',' {
|
|
comma_pos = paren_idx;
|
|
continue;
|
|
}
|
|
if !paren_content.is_ascii_digit() {
|
|
invalid = true;
|
|
break;
|
|
}
|
|
if comma_pos == 0 {
|
|
pair.0.push(paren_content);
|
|
} else {
|
|
pair.1.push(paren_content);
|
|
}
|
|
}
|
|
if !invalid {
|
|
let a = pair.0.parse::<i32>().unwrap();
|
|
let b = pair.1.parse::<i32>().unwrap();
|
|
pairs.push((a, b));
|
|
}
|
|
}
|
|
pairs
|
|
}
|
|
|
|
fn extract_mul_pairs_dont(line: &str) -> Vec<(i32, i32)> {
|
|
let mut pairs = Vec::new();
|
|
for (idx, _) in line.match_indices("mul(") {
|
|
if let Some(dont_func) = line[..idx].rfind("don't()") {
|
|
if let Some(do_func) = line[..idx].rfind("do()") {
|
|
if do_func < dont_func {
|
|
continue;
|
|
}
|
|
} else {
|
|
continue;
|
|
}
|
|
}
|
|
let mut invalid = false;
|
|
let mut comma_pos = 0;
|
|
let mut pair = ("".to_string(), "".to_string());
|
|
// max length of parenthesis == 9
|
|
for paren_idx in 0..9 {
|
|
let paren_content = match line.as_bytes().get(idx + 4 + paren_idx) {
|
|
Some(content) => *content as char,
|
|
None => {
|
|
invalid = true;
|
|
break;
|
|
}
|
|
};
|
|
if paren_content == ')' {
|
|
if comma_pos == 0 {
|
|
invalid = true;
|
|
}
|
|
break;
|
|
}
|
|
if paren_content == ',' {
|
|
comma_pos = paren_idx;
|
|
continue;
|
|
}
|
|
if !paren_content.is_ascii_digit() {
|
|
invalid = true;
|
|
break;
|
|
}
|
|
if comma_pos == 0 {
|
|
pair.0.push(paren_content);
|
|
} else {
|
|
pair.1.push(paren_content);
|
|
}
|
|
}
|
|
if !invalid {
|
|
let a = pair.0.parse::<i32>().unwrap();
|
|
let b = pair.1.parse::<i32>().unwrap();
|
|
pairs.push((a, b));
|
|
}
|
|
}
|
|
pairs
|
|
}
|
|
|
|
pub fn process_part2(input: &str) -> i32 {
|
|
input
|
|
.lines()
|
|
.map(extract_mul_pairs_dont)
|
|
.map(|pairs| pairs.iter().map(|(a, b)| a * b).sum::<i32>())
|
|
.sum()
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use std::fs;
|
|
|
|
use super::*;
|
|
|
|
const INPUT: &str =
|
|
"xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))mul( 1, 3)";
|
|
|
|
const INPUT_2: &str =
|
|
"xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))";
|
|
|
|
#[test]
|
|
fn part1() {
|
|
let result = process_part1(INPUT);
|
|
assert_eq!(result, 161);
|
|
}
|
|
|
|
#[test]
|
|
fn res1() {
|
|
let root = env!("CARGO_MANIFEST_DIR");
|
|
let content = fs::read_to_string(format!("{root}/resources/3_input.txt")).unwrap();
|
|
let result = process_part1(&content);
|
|
assert_eq!(result, 183788984);
|
|
}
|
|
|
|
#[test]
|
|
fn part2() {
|
|
let result = process_part2(INPUT_2);
|
|
assert_eq!(result, 48);
|
|
}
|
|
}
|