2023 - Day 04

2023/src/bin/day04.rs

@@ -0,0 +1,135 @@
+#![feature(test)]
+use anyhow::Result;
+use aoc::Solver;
+
+// -- Runners --
+fn main() -> Result<()> {
+    Day::solve()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn part1_test1() -> Result<()> {
+        Day::test(Day::part1, "test-1", 13)
+    }
+
+    #[test]
+    fn part1_solution() -> Result<()> {
+        Day::test(Day::part1, "input", 24706)
+    }
+
+    #[test]
+    fn part2_test1() -> Result<()> {
+        Day::test(Day::part2, "test-1", 30)
+    }
+
+    #[test]
+    fn part2_solution() -> Result<()> {
+        Day::test(Day::part2, "input", 13114317)
+    }
+
+    // Benchmarks
+    extern crate test;
+    #[bench]
+    #[ignore]
+    fn part1_bench(b: &mut test::Bencher) {
+        Day::benchmark(Day::part1, b)
+    }
+    #[bench]
+    #[ignore]
+    fn part2_bench(b: &mut test::Bencher) {
+        Day::benchmark(Day::part2, b)
+    }
+}
+
+// -- Solution --
+pub struct Day;
+impl aoc::Solver for Day {
+    type Output1 = usize;
+    type Output2 = usize;
+
+    fn day() -> u8 {
+        4
+    }
+
+    fn part1(input: &str) -> Self::Output1 {
+        // Calculate the score for every game and sum it
+        input
+            .lines()
+            .map(|line| {
+                // Get rid of the first part
+                let (_, line) = line
+                    .split_once(": ")
+                    .expect("Input should be formatted properly");
+
+                // Seperate the winning numbers and numbers we have
+                let (winning, numbers) = line
+                    .split_once(" | ")
+                    .expect("Input should be formatted properly");
+
+                // Parse the winning numbers
+                let winning: Vec<_> = winning.split(' ').flat_map(str::parse::<usize>).collect();
+                // Parse the numbers we have, check if they are a winning number and count the
+                // amount of winning numbers we have
+                let count = numbers
+                    .split(' ')
+                    .flat_map(str::parse::<usize>)
+                    .filter(|num| winning.contains(num))
+                    .count();
+
+                // Calculate the score
+                if count > 0 {
+                    return 2_usize.pow(count as u32 - 1);
+                }
+
+                0
+            })
+            .sum()
+    }
+
+    fn part2(input: &str) -> Self::Output2 {
+        // Calculate how many wins we have per game
+        let wins: Vec<_> = input
+            .lines()
+            .map(|line| {
+                // Get rid of the first part
+                let (_, line) = line
+                    .split_once(": ")
+                    .expect("Input should be formatted properly");
+
+                // Seperate the winning numbers and numbers we have
+                let (winning, numbers) = line
+                    .split_once(" | ")
+                    .expect("Input should be formatted properly");
+
+                // Parse the winning numbers
+                let winning: Vec<_> = winning.split(' ').flat_map(str::parse::<usize>).collect();
+                // Parse the numbers we have, check if they are a winning number and count the
+                // amount of winning numbers we have
+                numbers
+                    .split(' ')
+                    .flat_map(str::parse::<usize>)
+                    .filter(|num| winning.contains(num))
+                    .count()
+            })
+            .collect();
+
+        // Start out with one copy of every card
+        let mut copies = vec![1; wins.len()];
+
+        // Keep track of how many copies we get of every card
+        for (i, win) in wins.iter().enumerate() {
+            for j in (i + 1)..(i + win + 1) {
+                // Add the current amount of copies to the card we win
+                // e.g. we have 2 copies of the current card that has 3 wins, this means we add 2
+                // to the next 3 cards
+                copies[j] += copies[i]
+            }
+        }
+
+        copies.iter().sum()
+    }
+}