From 6be86a674eb82605d05c1b29cbee325c767027a1 Mon Sep 17 00:00:00 2001
From: Leandro Lisboa Penz <lpenz@lpenz.org>
Date: Mon, 4 Dec 2023 18:09:45 +0000
Subject: [PATCH] Day 04a

---
 Cargo.lock              |  9 +++++++++
 Cargo.toml              |  1 +
 day04/Cargo.toml        |  9 +++++++++
 day04/src/bin/day04a.rs | 29 +++++++++++++++++++++++++++
 day04/src/lib.rs        | 43 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 91 insertions(+)
 create mode 100644 day04/Cargo.toml
 create mode 100644 day04/src/bin/day04a.rs
 create mode 100644 day04/src/lib.rs

diff --git a/Cargo.lock b/Cargo.lock
index f26304e..ff38ca2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -169,6 +169,15 @@ dependencies = [
  "sqrid",
 ]
 
+[[package]]
+name = "day04"
+version = "0.1.0"
+dependencies = [
+ "aoc",
+ "color-eyre",
+ "nom",
+]
+
 [[package]]
 name = "either"
 version = "1.9.0"
diff --git a/Cargo.toml b/Cargo.toml
index 7ebe468..f89f367 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,5 +6,6 @@ members = [
     "day01",
     "day02",
     "day03",
+    "day04",
 ]
 
diff --git a/day04/Cargo.toml b/day04/Cargo.toml
new file mode 100644
index 0000000..514e63f
--- /dev/null
+++ b/day04/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "day04"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+aoc = { path = "../aoc" }
+color-eyre = "0.6.2"
+nom = "7.1.3"
diff --git a/day04/src/bin/day04a.rs b/day04/src/bin/day04a.rs
new file mode 100644
index 0000000..169ed57
--- /dev/null
+++ b/day04/src/bin/day04a.rs
@@ -0,0 +1,29 @@
+// Copyright (C) 2023 Leandro Lisboa Penz <lpenz@lpenz.org>
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+
+use std::io::{stdin, BufRead};
+
+use day04::*;
+
+fn process(bufin: impl BufRead) -> Result<u32> {
+    let input = parser::parse(bufin)?;
+    Ok(input
+        .into_iter()
+        .map(|(winners, have)| have.into_iter().filter(|h| winners.contains(h)).count() as u32)
+        .filter(|m| m > &0)
+        .map(|m| 2_u32.pow(m - 1))
+        .sum())
+}
+
+#[test]
+fn test() -> Result<()> {
+    assert_eq!(process(EXAMPLE.as_bytes())?, 13);
+    Ok(())
+}
+
+fn main() -> Result<()> {
+    color_eyre::install()?;
+    println!("{}", process(stdin().lock())?);
+    Ok(())
+}
diff --git a/day04/src/lib.rs b/day04/src/lib.rs
new file mode 100644
index 0000000..17903db
--- /dev/null
+++ b/day04/src/lib.rs
@@ -0,0 +1,43 @@
+// Copyright (C) 2023 Leandro Lisboa Penz <lpenz@lpenz.org>
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+
+pub use color_eyre::{eyre::eyre, Result};
+
+pub const EXAMPLE: &str = "Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
+Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
+Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
+Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
+Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
+Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11
+";
+
+pub mod parser {
+    use aoc::parser::*;
+
+    // use super::*;
+
+    fn line(input: &str) -> IResult<&str, (Vec<u32>, Vec<u32>)> {
+        let (input, _) = bytes::tag("Card")(input)?;
+        let (input, _) = character::space1(input)?;
+        let (input, _) = character::u32(input)?;
+        let (input, _) = bytes::tag(":")(input)?;
+        let (input, _) = character::space1(input)?;
+        let (input, winners) = multi::separated_list1(character::space1, character::u32)(input)?;
+        let (input, _) = bytes::tag(" |")(input)?;
+        let (input, _) = character::space1(input)?;
+        let (input, have) = multi::separated_list1(character::space1, character::u32)(input)?;
+        let (input, _) = character::newline(input)?;
+        Ok((input, (winners, have)))
+    }
+
+    pub fn parse(mut bufin: impl BufRead) -> Result<Vec<(Vec<u32>, Vec<u32>)>> {
+        aoc::parse_with!(multi::many1(line), bufin)
+    }
+}
+
+#[test]
+fn test() -> Result<()> {
+    assert_eq!(parser::parse(EXAMPLE.as_bytes())?.len(), 6);
+    Ok(())
+}