advent_of_code_2022/aoc_13a/src/main.rs

159 lines
4.4 KiB
Rust

use std::fs::File;
use std::io::{self, BufRead};
use std::path::Path;
use std::cmp::Ordering;
#[derive(Debug)]
enum Elem {
Number(u8),
List(Vec<Elem>),
}
use crate::Elem::{Number, List};
// I modified my input because the only 2 digits number was 10
// I replaced all 10s with ':' so that I can parse more easely
fn parse_line(line: &str, index: usize) -> (Elem, usize) {
let mut list: Vec<Elem> = vec![];
let mut len = 0;
while index + len < line.len() {
let c = line.as_bytes()[index + len];
len += 1;
match c {
b'[' => {
let (sublist, sublist_len) = parse_line(line, index + len);
len += sublist_len;
list.push(sublist);
},
b']' => return (List(list), len),
b'0'..=b':' => list.push(Number(c - b'0')),
_ => (),
};
}
unreachable!("parse_line end of function");
}
fn compare(lhs: &Elem, rhs: &Elem) -> Ordering {
let mut lhs_v = &vec![];
let mut rhs_v = &vec![];
if let List(a) = lhs {
lhs_v = a;
}
if let List(a) = rhs {
rhs_v = a;
}
for i in 0..lhs_v.len() {
if i >= rhs_v.len() {
return Ordering::Greater;
}
let compare_result = match (&lhs_v[i], &rhs_v[i]) {
(List(_), List(_)) => compare(&lhs_v[i], &rhs_v[i]),
(List(_), Number(b)) => compare(&lhs_v[i], &List(vec![Number(*b)])),
(Number(a), List(_)) => compare(&List(vec![Number(*a)]), &rhs_v[i]),
(Number(a), Number(b)) => a.cmp(b),
};
if compare_result != Ordering::Equal {
return compare_result;
}
}
if rhs_v.len() > lhs_v.len() {
return Ordering::Less;
}
Ordering::Equal
}
fn main() {
let file_path = String::from("input");
println!("In file {}", file_path);
let mut data: Vec<Elem> = vec![];
if let Ok(lines) = read_lines(file_path) {
// Consumes the iterator, returns an (Optional) String
for (i, line) in lines.enumerate() {
if let Ok(ip) = line {
match i % 3 {
0..=1 => data.push(parse_line(&ip, 1).0),
_ => (),
}
}
}
}
let mut ret = 0;
for i in (0..data.len()).filter(|x| x % 2 == 0) {
if compare(&data[i], &data[i+1]) == Ordering::Less {
ret += i / 2 + 1;
}
}
println!("{}", ret);
}
fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
where P: AsRef<Path>, {
let file = File::open(filename)?;
Ok(io::BufReader::new(file).lines())
}
#[cfg(test)]
fn compare_all_test_tool(lhs: &Elem, rhs: &Elem) {
assert_eq!(compare(&lhs, &rhs), Ordering::Less);
assert_eq!(compare(&rhs, &lhs), Ordering::Greater);
assert_eq!(compare(&rhs, &rhs), Ordering::Equal);
assert_eq!(compare(&lhs, &lhs), Ordering::Equal);
}
#[cfg(test)]
fn parse_all_test_tool(lhs: &Elem, rhs: &Elem, lhs_s: &str, rhs_s: &str) {
let lhs_s = parse_line(lhs_s, 1).0;
assert_eq!(compare(&lhs, &lhs_s), Ordering::Equal);
let rhs_s = parse_line(rhs_s, 1).0;
assert_eq!(compare(&rhs, &rhs_s), Ordering::Equal);
}
#[cfg(test)]
fn all_test_tool(lhs: &Elem, rhs: &Elem, lhs_s: &str, rhs_s: &str) {
parse_all_test_tool(&lhs, &rhs, lhs_s, rhs_s);
compare_all_test_tool(&lhs, &rhs);
}
#[test]
fn simple_list() {
let lhs_s = "[1,1,2]";
let rhs_s = "[1,3,1]";
let lhs = List(vec![Number(1), Number(1), Number(2)]);
let rhs = List(vec![Number(1), Number(3), Number(1)]);
all_test_tool(&lhs, &rhs, lhs_s, rhs_s);
}
#[test]
fn simple_list_with_conversion() {
let lhs_s = "[1,1,2]";
let rhs_s = "[1,[3],1]";
let lhs = List(vec![Number(1), Number(1), Number(2)]);
let rhs = List(vec![Number(1), List(vec![Number(3)]), Number(1)]);
all_test_tool(&lhs, &rhs, lhs_s, rhs_s);
}
#[test]
fn recursive_empty_list_simple() {
let lhs_s = "[[]]";
let rhs_s = "[[[]]]";
let lhs = List(vec![List(vec![])]);
let rhs = List(vec![List(vec![List(vec![])])]);
all_test_tool(&lhs, &rhs, lhs_s, rhs_s);
}
#[test]
fn recursive_empty_list() {
let lhs_s = "[[[[]]]]";
let rhs_s = "[[[[[]]]]]";
let lhs = List(vec![List(vec![List(vec![List(vec![])])])]);
let rhs = List(vec![List(vec![List(vec![List(vec![List(vec![])])])])]);
all_test_tool(&lhs, &rhs, lhs_s, rhs_s);
}