day 4, tbf I finished awhile ago

src/day4.rs

@@ -0,0 +1,69 @@
+use std::collections::HashSet;
+use std::fs;
+
+pub fn run() {
+    println!("Day 4:");
+    let input = fs::read_to_string("./inputs/day4.txt").expect("Could not read file");
+
+    println!("\tPart 1: {}", part1(&input));
+    // println!("\tPart 2: {}", part2(&input));
+}
+
+fn part1(cards: &str) -> usize {
+    let mut total_wins = 0;
+    for card in cards.lines() {
+        let (_, card_numbers) = card.split_once(':').unwrap();
+        let (winners_raw, chances_raw) = card_numbers.split_once('|').unwrap();
+
+        let winners = winners_raw
+            .split(' ')
+            .filter(|s| !s.is_empty())
+            .map(|win| win.trim().parse::<usize>().unwrap())
+            .collect::<HashSet<usize>>();
+        let chances = chances_raw
+            .split(' ')
+            .filter(|s| !s.is_empty())
+            .map(|chance| chance.trim().parse::<usize>().unwrap())
+            .collect::<HashSet<usize>>();
+
+        let wins = winners.intersection(&chances).count();
+        if wins != 0 {
+            total_wins += usize::pow(2, wins.saturating_sub(1) as u32);
+        }
+    }
+
+    total_wins
+}
+
+fn part2(schematic: &str) -> usize {
+    todo!()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let input = "Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
+Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
+Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
+Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
+Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
+Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11";
+
+        assert_eq!(part1(input), 13);
+    }
+
+    #[test]
+    fn test_2() {
+        let input = "Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
+Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
+Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
+Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
+Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
+Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11";
+
+        assert_eq!(part2(input), 467835);
+    }
+}

src/main.rs

@@ -4,10 +4,12 @@ extern crate scan_fmt;
 mod day1;
 mod day2;
 mod day3;
+mod day4;
 
 fn main() {
     println!("Running Advent of Code 2023");
     day1::run();
     day2::run();
     day3::run();
+    day4::run();
 }