1 files changed, 86 insertions, 0 deletions
diff --git a/2023/Rust/src/day4.rs b/2023/Rust/src/day4.rs
new file mode 100644
index 0000000..f4543e8
--- /dev/null
+++ b/2023/Rust/src/day4.rs
@@ -0,0 +1,86 @@
+#[derive(Debug)]
+struct ScratchCard {
+    winning: Vec<u32>,
+    numbers: Vec<u32>,
+    cnt: usize,
+}
+
+impl ScratchCard {
+    fn get_matching(&self) -> u32 {
+        let mut cnt = 0;
+        for number in self.numbers.iter() {
+            if self.winning.contains(&number) {
+                cnt += 1;
+            }
+        }
+        cnt
+    }
+}
+
+impl From<&str> for ScratchCard {
+    fn from(value: &str) -> Self {
+        let (_, sets) = value.split_once(':').expect("Should be splittable by ':'");
+        let (winning, numbers) = sets.split_once('|').expect("Should be splittable by '|'");
+        let (winning, numbers) = (
+            winning
+                .trim_start()
+                .trim_end()
+                .split(' ')
+                .filter(|x| x.parse::<u32>().is_ok())
+                .map(|x| x.parse::<u32>().unwrap())
+                .collect::<Vec<u32>>(),
+            numbers
+                .trim_start()
+                .trim_end()
+                .split(' ')
+                .filter(|x| x.parse::<u32>().is_ok())
+                .map(|x| x.parse::<u32>().unwrap())
+                .collect::<Vec<u32>>(),
+        );
+        Self {
+            winning,
+            numbers,
+            cnt: 1,
+        }
+    }
+}
+
+fn solve_part_one(data: &str) -> u32 {
+    let mut scratch_cards: Vec<ScratchCard> = vec![];
+    for line in data.lines() {
+        scratch_cards.push(ScratchCard::from(line))
+    }
+    scratch_cards
+        .iter()
+        .map(|card| card.get_matching())
+        .filter(|x| *x > 0)
+        .map(|x| 2_u32.pow(std::cmp::max(x - 1, 0) as u32))
+        .sum::<u32>()
+}
+
+fn solve_part_two(data: &str) -> u32 {
+    let mut scratch_cards: Vec<ScratchCard> = vec![];
+    for line in data.lines() {
+        scratch_cards.push(ScratchCard::from(line))
+    }
+    let n = scratch_cards.len();
+    for i in 0..n - 1 {
+        let matches = scratch_cards[i].get_matching();
+        let cnt = scratch_cards[i].cnt;
+        for _ in 0..cnt {
+            for j in (i + 1)..(i + matches as usize + 1) {
+                scratch_cards[j].cnt += 1;
+            }
+        }
+    }
+    scratch_cards.iter().map(|card| card.cnt).sum::<usize>() as u32
+}
+
+fn main() {
+    let test_1 = include_str!("../input/day4.test");
+    let prod = include_str!("../input/day4.prod");
+    println!("part_1 test: {:?}", solve_part_one(test_1));
+    println!("part_1 prod {:?}", solve_part_one(prod));
+    println!("part_2 test: {:?}", solve_part_two(test_1));
+    println!("part_2 prod {:?}", solve_part_two(prod));
+}