day 2 solution

janky and not expandable but it works

day_2/src/main.rs

@@ -1,3 +1,77 @@
+use std::collections::HashMap;
+use std::{fs, ops::Deref};
+
+const PATH: &str = "src/input";
+
+const LOSS_PTS: u32 = 0;
+const DRAW_PTS: u32 = 3;
+const WIN_PTS: u32 = 6;
+
+const ROCK: u8 = 1;
+const PAPER: u8 = 2;
+const SCISSORS: u8 = 3;
+
 fn main() {
-    println!("Hello, world!");
+    part_1();
+    part_2();
+}
+
+fn part_1() {
+    let mut game_score: HashMap<(u8, u8), u32> = HashMap::new();
+    game_score.insert((ROCK, ROCK), DRAW_PTS);
+    game_score.insert((PAPER, PAPER), DRAW_PTS);
+    game_score.insert((SCISSORS, SCISSORS), DRAW_PTS);
+
+    game_score.insert((PAPER, ROCK), LOSS_PTS);
+    game_score.insert((ROCK, SCISSORS), LOSS_PTS);
+    game_score.insert((SCISSORS, PAPER), LOSS_PTS);
+
+    game_score.insert((ROCK, PAPER), WIN_PTS);
+    game_score.insert((SCISSORS, ROCK), WIN_PTS);
+    game_score.insert((PAPER, SCISSORS), WIN_PTS);
+
+    let data = fs::read_to_string(PATH).expect("Error reading file");
+    let mut total_score = 0;
+    for line in data.split("\n") {
+        if line.len() > 0 {
+            let opponent = line.as_bytes().get(0).unwrap().deref() - b'A' + 1;
+            let player = line.as_bytes().get(2).unwrap().deref() - b'X' + 1;
+            let score = game_score.get(&(opponent, player)).unwrap() + (player as u32);
+            total_score += score;
+        }
+    }
+    println!("PART 1 total_score={}", total_score);
+}
+
+fn part_2() {
+    let mut choice_score: HashMap<(char, char), u8> = HashMap::new();
+    choice_score.insert(('A', 'X'), SCISSORS);
+    choice_score.insert(('A', 'Y'), ROCK);
+    choice_score.insert(('A', 'Z'), PAPER);
+
+    choice_score.insert(('B', 'X'), ROCK);
+    choice_score.insert(('B', 'Y'), PAPER);
+    choice_score.insert(('B', 'Z'), SCISSORS);
+
+    choice_score.insert(('C', 'X'), PAPER);
+    choice_score.insert(('C', 'Y'), SCISSORS);
+    choice_score.insert(('C', 'Z'), ROCK);
+
+    let mut game_score: HashMap<char, u32> = HashMap::new();
+    game_score.insert('X', 0);
+    game_score.insert('Y', 3);
+    game_score.insert('Z', 6);
+
+    let data = fs::read_to_string(PATH).expect("Error reading file");
+    let mut total_score: u32 = 0;
+    for line in data.split("\n") {
+        if line.len() > 0 {
+            let opponent = line.chars().nth(0).unwrap();
+            let player = line.chars().nth(2).unwrap();
+
+            total_score += *(choice_score.get(&(opponent, player)).unwrap_or(&0)) as u32
+                + *game_score.get(&player).unwrap_or(&0);
+        }
+    }
+    println!("PART 2 total_score={}", total_score);
 }