Advent of code 2020
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90 lines
2.4 KiB

use std::fs;
use std::fs::File;
use std::io::{prelude::*, BufReader};
use std::error::Error;
use regex::Regex;
pub fn aoc_01_both(filename: &str) -> Result<(), Box<dyn Error>> {
let file = File::open(filename).expect("No file");
let br = BufReader::new(file);
let mut v: Vec<i64> = vec![];
for line in br.lines() {
v.push(line?
.trim()
.parse().unwrap());
}
for i in 0..v.len()-2 {
for j in i+1..v.len()-1 {
if v[i] + v[j] == 2020 {
println!("aoc_01_01 result: {}", v[i]*v[j]);
}
}
}
for i in 0..v.len()-3 {
for j in i+1..v.len()-2 {
for k in j+1..v.len()-1 {
if v[i] + v[j] + v[k] == 2020 {
println!("aoc_01_02 result: {}", v[i] * v[j] * v[k]);
}
}
}
}
return Ok(());
}
pub fn aoc_02(filename: &str) -> Result<(), Box<dyn Error>> {
let contents = fs::read_to_string(filename)?;
let pairs: Vec<Vec<String>> = contents.lines().map(|line| {
line.split(":").map(|s| String::from(s)).collect()
}).collect();
aoc_02_01(&pairs).unwrap();
aoc_02_02(&pairs).unwrap();
Ok(())
}
fn aoc_02_01(pairs: &Vec<Vec<String>>) -> Result<(), Box<dyn Error>> {
let mut valid = 0;
let rules_re = Regex::new(r"(\d*)-(\d*) ([a-z])").unwrap();
for i in 0..pairs.len() {
let rule = rules_re.captures(&pairs[i][0]).unwrap();
let min = rule[1].parse::<usize>().unwrap();
let max = rule[2].parse::<usize>().unwrap();
let matches: usize = pairs[i][1].matches(&rule[3]).count();
if matches >= min && matches <= max {
valid += 1;
}
}
println!("2_1 had {}/{} valid passwords", valid, pairs.len());
return Ok(());
}
fn aoc_02_02(pairs: &Vec<Vec<String>>) -> Result<(), Box<dyn Error>> {
let mut valid = 0;
let rules_re = Regex::new(r"(\d*)-(\d*) ([a-z])").unwrap();
for i in 0..pairs.len() {
let rule = rules_re.captures(&pairs[i][0]).unwrap();
let first = rule[1].parse::<usize>().unwrap();
let sec = rule[2].parse::<usize>().unwrap();
let m1 = pairs[i][1].as_bytes()[first] == rule[3].as_bytes()[0];
let m2 = pairs[i][1].as_bytes()[sec] == rule[3].as_bytes()[0];
if (m1 || m2) && !(m1 && m2) {
valid += 1;
}
}
println!("2_2 had {}/{} valid passwords", valid, pairs.len());
return Ok(());
}