[TASK] Solved day 2

Cargo.lock

@@ -3,3 +3,55 @@
 [[package]]
 name = "advent-of-code-2020-rust"
 version = "0.1.0"
+dependencies = [
+ "lazy_static",
+ "regex",
+]
+
+[[package]]
+name = "aho-corasick"
+version = "0.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
+[[package]]
+name = "memchr"
+version = "2.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
+
+[[package]]
+name = "regex"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38cf2c13ed4745de91a5eb834e11c00bcc3709e773173b2ce4c56c9fbde04b9c"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+ "thread_local",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.6.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b181ba2dcf07aaccad5448e8ead58db5b742cf85dfe035e2227f137a539a189"
+
+[[package]]
+name = "thread_local"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
+dependencies = [
+ "lazy_static",
+]

Cargo.toml

@@ -7,3 +7,5 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+regex = "1"
+lazy_static = "1.4.0"

input/day2_example.txt

@@ -0,0 +1,3 @@
+1-3 a: abcde
+1-3 b: cdefg
+2-9 c: ccccccccc

src/day1.rs

@@ -35,8 +35,6 @@ fn find_pairs_summing_to(nums: &Vec<u32>, target: u32) -> (u32, u32)  {
 
 fn find_triplet_summing_to(nums: &Vec<u32>, target: u32) -> (u32, u32, u32){
 
-
-
     for i in 0..nums.len() {
         for j in (0..nums.len()).rev() {
 

src/day2.rs

@@ -0,0 +1,64 @@
+use super::util;
+use regex::{Regex, Captures};
+use std::ops::BitXor;
+
+pub fn solve() {
+    let lines = util::read_file("input/day2.txt");
+    let passwords: Vec<Password> = lines.iter().map(|p| parse(p)).collect();
+
+    let part1 = passwords.iter().filter(|p| p.is_valid()).count();
+    println!("Day 2 Part 1: {}", part1);
+
+    let part2 = passwords.iter().filter(|p| p.is_valid2()).count();
+    println!("Day 2 Part 2: {}", part2);
+}
+
+
+
+
+fn parse(line: &String) -> Password {
+
+    lazy_static! {
+        static ref RE: Regex = Regex::new(r"^(\d+)-(\d+) ([a-zA-Z]): ([a-zA-Z]+)$").unwrap();
+    }
+
+    if !RE.is_match(line.as_str()) {
+        panic!("Invalid line: {}", line);
+    }
+
+    let caps = RE.captures(line).unwrap();
+    return Password {
+        min: get_capture(&caps, 1).parse::<u32>().unwrap(),
+        max: get_capture(&caps, 2).parse::<u32>().unwrap(),
+        c: get_capture(&caps, 3).chars().next().unwrap(),
+        password: String::from(get_capture(&caps, 4))
+    }
+
+}
+
+fn get_capture(caps: &Captures, id: usize) -> String {
+    return caps.get(id).map_or(String::from(""), |m| String::from(m.as_str()));
+}
+
+// #[derive(Debug)]
+struct Password {
+    pub min: u32,
+    pub max: u32,
+    pub c: char,
+    pub password: String
+}
+
+impl Password {
+
+    fn is_valid(&self) -> bool {
+        let occ = self.password.chars().filter(|pc| pc == &self.c).count() as u32;
+        return occ >= self.min && occ <= self.max;
+    }
+
+    fn is_valid2(&self) -> bool {
+
+        return (self.password.chars().nth((self.min - 1) as usize) == Option::from(self.c)).bitxor(
+            self.password.chars().nth((self.max - 1) as usize) == Option::from(self.c));
+
+    }
+}

src/dayX.rs

@@ -0,0 +1,5 @@
+use super::util;
+
+pub fn solve() {
+    let lines = util::read_file("input/dayX.txt");
+}

src/main.rs

@@ -1,7 +1,9 @@
 use std::time::Instant;
+#[macro_use] extern crate lazy_static;
 
 mod util;
 mod day1;
+mod day2;
 
 fn main() {
 
@@ -13,11 +15,13 @@ fn main() {
     if day_arg_idx.is_some() {
         match args[day_arg_idx.unwrap() + 1].parse::<u8>().unwrap() {
             1 => day1::solve(),
+            2 => day2::solve(),
             _ => println!("This day is not yet implemented")
         }
     } else {
         // Solve all days:
         day1::solve();
+        day2::solve();
     }
 
     println!("Execution took {} μs", now.elapsed().as_micros());