add day7

Author: mirsella

2024/day7/.gitignore

@@ -0,0 +1,19 @@
+input.txt
+flamegraph.svg
+perf.data*
+### Rust
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb
+

2024/day7/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "da7"
+authors = ["mirsella <[email protected]>"]
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+regex = { workspace = true }
+itertools = { workspace = true }
+pathfinding = { workspace = true }
+rayon = { workspace = true }
+indexmap = { workspace = true }

2024/day7/src/main.rs

@@ -0,0 +1,86 @@
+use itertools::Itertools;
+
+fn part1(input: &str) -> usize {
+    let lines = input.lines().map(|l| {
+        let mut s = l
+            .split_whitespace()
+            .map(|s| s.trim_end_matches(':').parse::<usize>().unwrap());
+        (s.next().unwrap(), s.collect_vec())
+    });
+    fn try_operator(total: usize, values: &[usize], acc: usize) -> bool {
+        if (acc + values[0] == total || acc * values[0] == total) && values.len() == 1 {
+            return true;
+        }
+        if values.len() > 1 {
+            if try_operator(total, &values[1..], acc + values[0]) {
+                return true;
+            }
+            if try_operator(total, &values[1..], acc * values[0]) {
+                return true;
+            }
+        }
+        false
+    }
+    lines
+        .filter_map(|(total, values)| try_operator(total, &values[1..], values[0]).then_some(total))
+        .sum()
+}
+
+fn part2(input: &str) -> usize {
+    let lines = input.lines().map(|l| {
+        let mut s = l
+            .split_whitespace()
+            .map(|s| s.trim_end_matches(':').parse::<usize>().unwrap());
+        (s.next().unwrap(), s.collect_vec())
+    });
+    fn try_operator(total: usize, values: &[usize], acc: usize) -> bool {
+        let add = values[0] + acc;
+        let mul = values[0] * acc;
+        let concat = format!("{}{}", acc, values[0]).parse::<usize>().unwrap();
+        if (add == total || mul == total || concat == total) && values.len() == 1 {
+            return true;
+        }
+        if values.len() > 1 {
+            if try_operator(total, &values[1..], add) {
+                return true;
+            }
+            if try_operator(total, &values[1..], mul) {
+                return true;
+            }
+            if try_operator(total, &values[1..], concat) {
+                return true;
+            }
+        }
+        false
+    }
+    lines
+        .filter_map(|(total, values)| try_operator(total, &values[1..], values[0]).then_some(total))
+        .sum()
+}
+
+fn main() {
+    let input = include_str!("../input.txt");
+    println!("Part 1: {}", part1(input));
+    println!("Part 2: {}", part2(input));
+}
+
+#[cfg(test)]
+mod tests {
+    const INPUT: &str = "190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20";
+    #[test]
+    fn part1() {
+        assert_eq!(super::part1(INPUT), 3749);
+    }
+    #[test]
+    fn part2() {
+        assert_eq!(super::part2(INPUT), 11387);
+    }
+}