Day 4 aoc part 1 finished, almost caught up now

advent_of_code/2023/4/src/main.rs

@@ -0,0 +1,72 @@
+use std::collections::HashSet;
+
+use nom::{
+    bytes::complete::tag,
+    character::complete::{digit1, multispace1, u32},
+    multi::separated_list1,
+    sequence::{preceded, separated_pair, tuple},
+    IResult,
+};
+
+fn parse_input(input: &str) -> IResult<&str, Vec<(Vec<u32>, Vec<u32>)>> {
+    let (input, result) = separated_list1(
+        multispace1,
+        preceded(
+            tuple((tag("Card"), multispace1, digit1, tag(":"), multispace1)),
+            separated_pair(
+                separated_list1(multispace1, u32),
+                tuple((multispace1, tag("|"), multispace1)),
+                separated_list1(multispace1, u32),
+            ),
+        ),
+    )(input)?;
+
+    Ok((input, result))
+}
+
+fn card_score(card: &(Vec<u32>, Vec<u32>)) -> u32 {
+    let winning_numbers: HashSet<&u32> = HashSet::from_iter(card.0.iter());
+
+    let wins = card
+        .1
+        .iter()
+        .filter(|&number| winning_numbers.contains(number))
+        .count();
+
+    if wins == 0 {
+        0
+    } else {
+        2_u32.pow(wins as u32 - 1)
+    }
+}
+
+fn solve_1(scratchcards: &[(Vec<u32>, Vec<u32>)]) -> u32 {
+    scratchcards.iter().map(card_score).sum()
+}
+
+fn main() {
+    println!("Hello, this is Patrick!");
+
+    let input_txt = include_str!("../input.txt");
+
+    let (_, scratchcards) = parse_input(input_txt).unwrap();
+
+    println!(
+        "The scratch cards are worth {} points",
+        solve_1(&scratchcards[..])
+    );
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let input_text = include_str!("../test_input.txt");
+
+        let (_, scratchcards) = parse_input(input_text).unwrap();
+
+        assert_eq!(solve_1(&scratchcards[..]), 13);
+    }
+}