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-rw-r--r--2023/day4/src/lib.rs128
1 files changed, 128 insertions, 0 deletions
diff --git a/2023/day4/src/lib.rs b/2023/day4/src/lib.rs
new file mode 100644
index 0000000..cc3742a
--- /dev/null
+++ b/2023/day4/src/lib.rs
@@ -0,0 +1,128 @@
+fn parse(input: &str) -> Vec<String> {
+ input
+ .trim_end()
+ .split('\n')
+ .map(|x| {
+ let b = x.to_string();
+ let k = b.split(':').last().unwrap();
+
+ return k.trim().to_string();
+ })
+ .collect()
+}
+
+pub fn part1(input: &str) -> u32 {
+ let mut res: u32 = 0;
+
+ let cards: Vec<String> = parse(input);
+ for card in cards {
+ let numbers: Vec<String> = card.split('|').map(|x| x.trim().to_string()).collect();
+ assert_eq!(numbers.len(), 2);
+
+ let winnings: Vec<_> = numbers[0]
+ .replace(" ", " ")
+ .split(' ')
+ .map(|x| x.trim().parse::<u32>().unwrap())
+ .collect();
+ let plays: Vec<_> = numbers[1]
+ .replace(" ", " ")
+ .split(' ')
+ .map(|x| x.trim().parse::<u32>().unwrap())
+ .collect();
+
+ let mut k = 0;
+ for win in winnings {
+ if plays.contains(&win) {
+ k = if k == 0 { 1 } else { k * 2 };
+ }
+ }
+ res += k;
+ }
+
+ res
+}
+
+//
+//
+//
+// 1 -> 4 | x
+// 2 -> 2 | y x
+// 3 -> 2 | y y y x
+// 4 -> 1 | y y y y y y y x
+// 5 -> 0 | y y y y y y y y y y y y y x
+// 6 -> 0 | x
+//
+//
+pub fn part2(input: &str) -> u32 {
+ let mut res: u32 = 0;
+
+ let cards: Vec<String> = parse(input);
+ let mut incr: Vec<u32> = Vec::new();
+ incr.resize_with(cards.len(), Default::default);
+
+ let mut i = 0;
+ for card in cards {
+ let numbers: Vec<String> = card.split('|').map(|x| x.trim().to_string()).collect();
+ assert_eq!(numbers.len(), 2);
+
+ let winnings: Vec<_> = numbers[0]
+ .replace(" ", " ")
+ .split(' ')
+ .map(|x| x.trim().parse::<u32>().unwrap())
+ .collect();
+ let plays: Vec<_> = numbers[1]
+ .replace(" ", " ")
+ .split(' ')
+ .map(|x| x.trim().parse::<u32>().unwrap())
+ .collect();
+
+ let mut k = 0;
+ for win in winnings {
+ if plays.contains(&win) {
+ k += 1;
+ }
+ }
+
+ for j in i + 1..i + 1 + k {
+ incr[j] += 1 + incr[i];
+ }
+
+ res += 1 + incr[i];
+ i += 1;
+ }
+
+ res
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn example_part1() {
+ let input = include_str!("../example.txt");
+ let result = part1(input);
+ assert_eq!(result, 13);
+ }
+
+ #[test]
+ fn input_part1() {
+ let input = include_str!("../input.txt");
+ let result = part1(input);
+ assert_eq!(result, 25174);
+ }
+
+ #[test]
+ fn example_part2() {
+ let input = include_str!("../example.txt");
+ let result = part2(input);
+ assert_eq!(result, 30);
+ }
+
+ #[test]
+ fn input_part2() {
+ let input = include_str!("../input.txt");
+ let result = part2(input);
+ assert_eq!(result, 6420979);
+ }
+}