From c3773862a4e0d9638566b767940728f4fb906a41 Mon Sep 17 00:00:00 2001
From: "Timothy J. Warren" <tim@timshomepage.net>
Date: Fri, 8 Dec 2023 12:08:55 -0500
Subject: [PATCH] Complete 2023 day4 part 1

---
 2023/day4/src/main.rs | 83 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 63 insertions(+), 20 deletions(-)

diff --git a/2023/day4/src/main.rs b/2023/day4/src/main.rs
index 529d362..40e65ee 100644
--- a/2023/day4/src/main.rs
+++ b/2023/day4/src/main.rs
@@ -1,29 +1,64 @@
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::iter::FromIterator;
 
 const FILE_STR: &'static str = include_str!("input.txt");
 
-#[derive(Default, Debug)]
+#[derive(Debug, Default)]
 struct ScratchCard {
     winning: Vec<usize>,
     chosen: Vec<usize>,
+    chosen_winners: HashSet<usize>,
 }
 
 impl ScratchCard {
     fn new(winning: Vec<usize>, chosen: Vec<usize>) -> Self {
-        ScratchCard { winning, chosen }
+        ScratchCard {
+            winning,
+            chosen,
+            ..Self::default()
+        }
+    }
+
+    fn find_chosen_winners(&mut self) {
+        self.winning
+            .iter()
+            .filter(|w| self.chosen.contains(w))
+            .for_each(|cw| _ = self.chosen_winners.insert(*cw));
+    }
+
+    fn score(&mut self) -> usize {
+        self.find_chosen_winners();
+        if self.chosen_winners.is_empty() {
+            return 0;
+        }
+
+        let winner_count = self.chosen_winners.len() as u32;
+        usize::pow(2, winner_count - 1)
     }
 }
 
-type GameMap = HashMap<usize, ScratchCard>;
+#[derive(Debug, Default)]
+struct GameMap(HashMap<usize, ScratchCard>);
 
-/// Parse numbers from a line, separated/surrounded by whitespace
-fn parse_num_str(s: &str) -> Vec<usize> {
-    s.split_ascii_whitespace()
-        .filter(|s| s.len() > 0)
-        .map(|s| s.trim())
-        .map(|s| usize::from_str_radix(s, 10).unwrap())
-        .collect::<Vec<usize>>()
+impl GameMap {
+    fn parse(table: &str) -> Self {
+        Self(HashMap::from_iter(
+            table
+                .split('\n')
+                .filter(|s| s.len() > 0)
+                .map(parse_game_table_line),
+        ))
+    }
+
+    fn find_all_chosen_winners(&mut self) {
+        self.0.iter_mut().for_each(|(_, sc)| {
+            sc.find_chosen_winners();
+        })
+    }
+
+    fn get_score_sum(&mut self) -> usize {
+        self.0.iter_mut().map(|(_, sc)| sc.score()).sum()
+    }
 }
 
 fn parse_game_table_line(line: &str) -> (usize, ScratchCard) {
@@ -35,18 +70,19 @@ fn parse_game_table_line(line: &str) -> (usize, ScratchCard) {
     (card_num, ScratchCard::new(nums[0].clone(), nums[1].clone()))
 }
 
-fn parse_game_table(table: &str) -> GameMap {
-    HashMap::from_iter(
-        table
-            .split('\n')
-            .filter(|s| s.len() > 0)
-            .map(parse_game_table_line),
-    )
+/// Parse numbers from a line, separated/surrounded by whitespace
+fn parse_num_str(s: &str) -> Vec<usize> {
+    s.split_ascii_whitespace()
+        .filter(|s| s.len() > 0)
+        .map(|s| s.trim())
+        .map(|s| usize::from_str_radix(s, 10).unwrap())
+        .collect::<Vec<usize>>()
 }
 
 fn part_one() {
-    let map = parse_game_table(FILE_STR);
-    println!("{:#?}", map);
+    let mut map = GameMap::parse(FILE_STR);
+    let sum = map.get_score_sum();
+    println!("Part 1 Score Sum {}", sum);
 }
 
 fn main() {
@@ -57,4 +93,11 @@ fn main() {
 mod tests {
     use super::*;
     const EXAMPLE_FILE_STR: &'static str = include_str!("example_input.txt");
+
+    #[test]
+    fn test_part1_example() {
+        let mut map = GameMap::parse(EXAMPLE_FILE_STR);
+        let actual = map.get_score_sum();
+        assert_eq!(13, actual);
+    }
 }