day_7 part_1

Cargo.toml

@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 anyhow = "1.0.94"
+ilog = "1.0.1"
 itertools = "0.13.0"
 regex = "1.11.1"
 

src/day_7/mod.rs

@@ -0,0 +1,40 @@
+use core::f64;
+use std::iter;
+
+use itertools::Itertools;
+use regex::Regex;
+
+pub mod part_1;
+pub mod part_2;
+
+pub fn parse(input: &str) -> Vec<(u64, Vec<u64>)> {
+    let re_groups = Regex::new(r"(?P<test_val>\d+): (?P<nums>[\d ]+)").unwrap();
+    re_groups
+        .captures_iter(input)
+        .map(|cap| {
+            let test_val = cap["test_val"].parse().unwrap();
+            let nums = cap["nums"].split(' ').map(|x| x.parse().unwrap()).collect_vec();
+            (test_val, nums)
+        })
+        .collect_vec()
+}
+
+pub fn solutions<'a, 'b, 'c>(
+    vals: &'a [u64],
+    ops: &'b [fn(u64, u64) -> u64],
+) -> Box<dyn Iterator<Item = u64> + 'c>
+where
+    'a: 'c,
+    'b: 'c,
+{
+    match vals.len() {
+        1 => Box::new(iter::once(vals[0])),
+        n => {
+            let val = vals[n - 1];
+            Box::new(ops.iter().flat_map(move |op| {
+                let lefts = solutions(&vals[..n - 1], ops);
+                lefts.map(move |l| op(l, val))
+            }))
+        }
+    }
+}

src/day_7/part_1/dummy_input.txt

@@ -0,0 +1,9 @@
+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

src/day_7/part_1/mod.rs

@@ -0,0 +1,21 @@
+use std::iter;
+
+use itertools::Itertools;
+
+use super::{parse, solutions};
+
+#[cfg(test)]
+mod test;
+
+pub fn solve(input: &str) -> u64 {
+    let equations = parse(input);
+    const OPS: [fn(u64, u64) -> u64; 2] = [
+        u64::saturating_mul, 
+        u64::saturating_add
+    ];
+    equations
+        .iter()
+        .filter(|eq| solutions(&eq.1, &OPS).any(|sol| sol == eq.0))
+        .map(|eq| eq.0)
+        .sum()
+}

src/day_7/part_1/test.rs

@@ -0,0 +1,16 @@
+use super::solve;
+use crate::include_using_path;
+
+#[test]
+fn dummy_input() {
+    let input = include_using_path!("dummy_input.txt");
+    let result = solve(input);
+    assert_eq!(result, 3749);
+}
+
+#[test]
+fn solve_puzzle() {
+    let input = include_using_path!("input.txt");
+    let result = solve(input);
+    println!("Result: {}", result);
+}

src/lib.rs

@@ -10,6 +10,7 @@ mod day_3;
 mod day_4;
 mod day_5;
 mod day_6;
+mod day_7;
 
 macro_rules! include_using_path {
     ($relative_path:expr) => {{