day 7

2024/day07/src/lib.rs

@@ -0,0 +1,141 @@
+use helper::{parse_unwrap, Day, Variants};
+
+pub fn main() {
+    helper::main::<Day07>(include_str!("../input.txt"));
+}
+
+struct Day07;
+
+helper::define_variants! {
+    day => crate::Day07;
+    part1 {
+        basic => crate::part1,sample_count=1000;
+    }
+    part2 {
+        basic => crate::part2,sample_count=500;
+        no_string_fmt => crate::part2_no_string_fmt,sample_count=1000;
+    }
+}
+
+impl Day for Day07 {
+    fn part1() -> Variants {
+        part1_variants!(construct_variants)
+    }
+
+    fn part2() -> Variants {
+        part2_variants!(construct_variants)
+    }
+}
+
+fn part1(input: &str) -> u64 {
+    let mut total = 0;
+    for line in input.lines() {
+        let (result, values) = line.split_once(": ").unwrap();
+        let result = parse_unwrap(result);
+        let values = values.split(" ").map(parse_unwrap).collect::<Vec<_>>();
+
+        fn does_work(values: &[u64], result: u64) -> bool {
+            if values.len() == 1 {
+                return values[0] == result;
+            }
+
+            let l = *values.last().unwrap();
+            let next = &values[..(values.len() - 1)];
+
+            let mul_works = result % l == 0;
+            let sub_works = l <= result;
+
+            (mul_works && does_work(next, result / l)) || (sub_works && does_work(next, result - l))
+        }
+
+        if does_work(&values, result) {
+            total += result;
+        }
+    }
+
+    total
+}
+
+fn part2(input: &str) -> u64 {
+    let mut total = 0;
+    for line in input.lines() {
+        let (result, values) = line.split_once(": ").unwrap();
+        let result = parse_unwrap(result);
+        let values = values
+            .split(" ")
+            .map(|val| (val, parse_unwrap(val)))
+            .collect::<Vec<_>>();
+
+        fn does_work(values: &[(&str, u64)], result: u64) -> bool {
+            if values.len() == 1 {
+                return values[0].1 == result;
+            }
+
+            let (l_str, l) = *values.last().unwrap();
+            let next = &values[..(values.len() - 1)];
+
+            let mul_works = result % l == 0;
+            let sub_works = l <= result;
+
+            (mul_works && does_work(next, result / l))
+                || (sub_works && does_work(next, result - l))
+                || (result.to_string().ends_with(l_str)
+                    && does_work(next, result / (10_u64.pow(l_str.len() as u32))))
+        }
+
+        if does_work(&values, result) {
+            total += result;
+        }
+    }
+    total
+}
+
+fn part2_no_string_fmt(input: &str) -> u64 {
+    let mut total = 0;
+    for line in input.lines() {
+        let (result, values) = line.split_once(": ").unwrap();
+        let result = parse_unwrap(result);
+        let values = values
+            .split(" ")
+            .map(|val| (val, parse_unwrap(val)))
+            .collect::<Vec<_>>();
+
+        fn does_work(values: &[(&str, u64)], result: u64) -> bool {
+            if values.len() == 1 {
+                return values[0].1 == result;
+            }
+
+            let (l_str, l) = *values.last().unwrap();
+            let next = &values[..(values.len() - 1)];
+
+            let mul_works = result % l == 0;
+            let sub_works = l <= result;
+
+            (mul_works && does_work(next, result / l))
+                || (sub_works && does_work(next, result - l))
+                || {
+                    let thousand = 10_u64.pow(l_str.len() as u32);
+                    let concat_works = result % thousand == l;
+                    concat_works && does_work(next, result / thousand)
+                }
+        }
+
+        if does_work(&values, result) {
+            total += result;
+        }
+    }
+    total
+}
+
+helper::tests! {
+    day07 Day07;
+    part1 {
+        small => 3749;
+        default => 303876485655;
+    }
+    part2 {
+        small => 11387;
+        default => 0;
+    }
+}
+helper::benchmarks! {}

2024/day07/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    day07::main();
+}