added day02

Signed-off-by: Philip Molares <philip.molares@udo.edu>

day02/Cargo.lock

+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "aho-corasick"
+version = "0.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "day02"
+version = "0.1.0"
+dependencies = [
+ "regex",
+]
+
+[[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",
+]

day02/Cargo.toml

+[package]
+name = "day02"
+version = "0.1.0"
+authors = ["Philip Molares <philip.molares@udo.edu>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+regex = "1.1.9"

day02/src/main.rs

+use std::fs::File;
+use std::io::{self, prelude::*, BufReader};
+use std::str::FromStr;
+use regex::Regex;
+
+#[derive(Debug)]
+struct Entry {
+    min: usize,
+    max: usize,
+    character: char, 
+    password: String
+}
+
+impl FromStr for Entry {
+    type Err = std::num::ParseIntError;
+    
+    fn from_str(input: &str) -> Result<Self, Self::Err> {
+        let regex = Regex::new(r"^(?P<min>\d*)-(?P<max>\d*)\s(?P<character>[a-z]):\s(?P<password>[a-z]*)").unwrap();
+        let caps = regex.captures(input).unwrap();
+
+        let min = caps.name("min").unwrap()
+            .as_str()
+            .parse::<usize>()
+            .expect("Error: Could not parse min");
+
+        let max = caps.name("max").unwrap()
+            .as_str()
+            .parse::<usize>()
+            .expect("Error: Could not parse max");
+
+        let character = caps.name("character").unwrap()
+            .as_str()
+            .chars()
+            .next()
+            .unwrap();
+
+        let password = String::from(caps.name("password").unwrap()
+            .as_str());
+
+        Ok(Entry {
+            min: min,
+            max: max,
+            character: character,
+            password: password
+        })
+    }
+}
+
+impl Entry {
+    fn check_password(&self) -> bool {
+        let occourences = self.password.matches(self.character).count();
+        return occourences >= self.min && occourences <= self.max
+    }
+
+    fn check_password2(&self) -> bool {
+        let chars: Vec<char> = self.password.chars().collect();
+        return (chars[self.min - 1] == self.character) 
+            ^ (self.max <= self.password.len() && chars[self.max - 1] == self.character)
+    }
+}
+
+fn main() -> io::Result<()> {
+    println!("Advent of Code 2020 – Day 2:");
+
+    let file = File::open("input.txt")?;
+    let reader = BufReader::new(file);
+
+    let input = reader
+        .lines()
+        .map(|l| {
+           Entry::from_str(&l.unwrap()).unwrap()
+        })
+        .collect::<Vec<Entry>>();
+
+
+    let correct_passwords = input
+        .iter()
+        .map(|entry| entry.check_password())
+        .filter(|result| *result)
+        .count();
+
+    println!("Answer Part 1: {}", correct_passwords);
+    
+    // let file2 = File::open("input.txt")?;
+    // let reader2 = BufReader::new(file);
+
+    /* let input2 = reader2
+        .lines()
+        .map(|l| {
+           Entry::from_str(&l.unwrap()).unwrap()
+        })
+        .collect::<Vec<Entry>>(); */
+        
+    let correct_passwords2 = input
+        .iter()
+        .map(|entry| entry.check_password2())
+        .filter(|result| *result)
+        .count();
+
+    println!("Answer Part 2: {}", correct_passwords2);
+
+    Ok(())
+}