Advent 2023 Day 4

advent_of_code_2023/day4/main1.rs

@@ -0,0 +1,30 @@
+use std::fs::read_to_string;
+use std::collections::HashSet;
+
+fn main() {
+    let mut score = 0;
+
+    for line in read_to_string("input.txt").unwrap().lines() {
+        let (_, card) = line.split_once(':').unwrap();
+        let (numbers, winners) = card.split_once('|').unwrap();
+        
+        let numbers = numbers.split(' ').filter(|numstr| { !numstr.is_empty() }).map(|number| {
+            number.parse::<i32>().unwrap()
+        }).collect::<Vec<_>>();
+
+        let winners = winners.split(' ').filter(|numstr| { !numstr.is_empty() }).map(|number| {
+            number.parse::<i32>().unwrap()
+        }).collect::<HashSet<_>>();
+
+        let mut card_score = 0;
+        for number in numbers {
+            if winners.contains(&number) {
+                card_score = if card_score == 0 { 1 } else { card_score * 2 };
+            }
+        }
+        
+        score += card_score;
+    }
+
+    println!("score: {}", score);
+}