d4p1

2023/day04/src/lib.rs

@@ -26,8 +26,29 @@ impl Day for Day04 {
     }
 }
 
-fn part1(_input: &str) -> u64 {
+fn part1(input: &str) -> u64 {
-    0
+    input
+        .lines()
+        .map(|line| {
+            let mut numbers = line.split(':').nth(1).unwrap().split("|");
+            let winning = numbers
+                .next()
+                .unwrap()
+                .split_whitespace()
+                .collect::<Vec<_>>();
+            let you_have = numbers.next().unwrap().split_whitespace();
+
+            let win_amount = you_have
+                .filter(|have| winning.iter().any(|w| w == have))
+                .count();
+
+            if win_amount > 0 {
+                1 << (win_amount - 1)
+            } else {
+                0
+            }
+        })
+        .sum()
 }
 
 fn part2(_input: &str) -> u64 {
@@ -37,8 +58,8 @@ fn part2(_input: &str) -> u64 {
 helper::tests! {
     day04 Day04;
     part1 {
-        small => 0;
+        small => 13;
-        default => 0;
+        default => 24733;
     }
     part2 {
         small => 0;