From 49975b4b0f8ad512f097ebe6e068a86e95281c65 Mon Sep 17 00:00:00 2001
From: Adrian Groh <adrian.groh@t-online.de>
Date: Sat, 7 Dec 2024 13:34:43 +0100
Subject: [PATCH] Add day7

---
 day7/Cargo.lock  | 61 ++++++++++++++++++++++++++++++++++++++++++++++++
 day7/Cargo.toml  |  7 ++++++
 day7/src/main.rs | 48 +++++++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+)
 create mode 100644 day7/Cargo.lock
 create mode 100644 day7/Cargo.toml
 create mode 100644 day7/src/main.rs

diff --git a/day7/Cargo.lock b/day7/Cargo.lock
new file mode 100644
index 0000000..19b5bc4
--- /dev/null
+++ b/day7/Cargo.lock
@@ -0,0 +1,61 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22ec99545bb0ed0ea7bb9b8e1e9122ea386ff8a48c0922e43f36d45ab09e0e80"
+
+[[package]]
+name = "day7"
+version = "0.1.0"
+dependencies = [
+ "rayon",
+]
+
+[[package]]
+name = "either"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
+
+[[package]]
+name = "rayon"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b418a60154510ca1a002a752ca9714984e21e4241e804d32555251faf8b78ffa"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
diff --git a/day7/Cargo.toml b/day7/Cargo.toml
new file mode 100644
index 0000000..8d90871
--- /dev/null
+++ b/day7/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "day7"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+rayon = "1.10.0"
diff --git a/day7/src/main.rs b/day7/src/main.rs
new file mode 100644
index 0000000..8c0df1f
--- /dev/null
+++ b/day7/src/main.rs
@@ -0,0 +1,48 @@
+use rayon::prelude::*;
+
+fn parse(input: &str) -> Vec<Vec<usize>> {
+    input
+        .lines()
+        .map(|line| {
+            line.replace(':', "")
+                .split(' ')
+                .map(|num| num.parse().unwrap())
+                .collect()
+        })
+        .collect()
+}
+
+fn is_possible(res: usize, curr: usize, nums: &[usize], part2: bool) -> bool {
+    if curr > res {
+        return false;
+    }
+    if nums.is_empty() {
+        return res == curr;
+    }
+    is_possible(res, curr * nums[0], &nums[1..], part2)
+        || is_possible(res, curr + nums[0], &nums[1..], part2)
+        || if part2 {
+            is_possible(
+                res,
+                curr * 10usize.pow(nums[0].ilog10() + 1) + nums[0],
+                &nums[1..],
+                part2,
+            )
+        } else {
+            false
+        }
+}
+
+fn part12(input: &[Vec<usize>], part2: bool) -> usize {
+    input
+        .par_iter()
+        .filter(|l| is_possible(l[0], l[1], &l[2..], part2))
+        .map(|l| l[0])
+        .sum()
+}
+
+fn main() {
+    let input = parse(include_str!("../input.txt"));
+    println!("{}", part12(&input, false));
+    println!("{}", part12(&input, true));
+}