From 2e05ee3b588b6bced1b45c2dfcdb7a2ec4b3819a Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Wed, 6 Dec 2023 10:32:05 +0100
Subject: Add day6

---
 2023/Cargo.toml       |   2 +-
 2023/day6/Cargo.toml  |   8 ++++
 2023/day6/example.txt |   2 +
 2023/day6/input.txt   |   3 ++
 2023/day6/src/lib.rs  | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 116 insertions(+), 1 deletion(-)
 create mode 100644 2023/day6/Cargo.toml
 create mode 100644 2023/day6/example.txt
 create mode 100644 2023/day6/input.txt
 create mode 100644 2023/day6/src/lib.rs

diff --git a/2023/Cargo.toml b/2023/Cargo.toml
index 20df693..3a90b12 100644
--- a/2023/Cargo.toml
+++ b/2023/Cargo.toml
@@ -1,2 +1,2 @@
 [workspace]
-members = ["day1", "day2", "day3", "day4", "day5"]
+members = ["day1", "day2", "day3", "day4", "day5", "day6"]
diff --git a/2023/day6/Cargo.toml b/2023/day6/Cargo.toml
new file mode 100644
index 0000000..89d04ae
--- /dev/null
+++ b/2023/day6/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "day6"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/2023/day6/example.txt b/2023/day6/example.txt
new file mode 100644
index 0000000..28f5ae9
--- /dev/null
+++ b/2023/day6/example.txt
@@ -0,0 +1,2 @@
+Time:      7  15   30
+Distance:  9  40  200
diff --git a/2023/day6/input.txt b/2023/day6/input.txt
new file mode 100644
index 0000000..f4a8fdc
--- /dev/null
+++ b/2023/day6/input.txt
@@ -0,0 +1,3 @@
+Time:        41     66     72     66
+Distance:   244   1047   1228   1040
+
diff --git a/2023/day6/src/lib.rs b/2023/day6/src/lib.rs
new file mode 100644
index 0000000..b3e33cb
--- /dev/null
+++ b/2023/day6/src/lib.rs
@@ -0,0 +1,102 @@
+pub fn part1(input: &str) -> u64 {
+    let mut res: u64 = 1;
+
+    let td: Vec<Vec<_>> = input
+        .trim_end()
+        .split('\n')
+        .map(|x| {
+            x.split(':')
+                .nth(1)
+                .unwrap()
+                .trim()
+                .replace("    ", " ")
+                .replace("   ", " ")
+                .replace("  ", " ")
+                .split(' ')
+                .map(|y| y.parse::<u64>().unwrap())
+                .collect()
+        })
+        .collect();
+
+    assert_eq!(td.len(), 2);
+    let (t, d) = (&td[0], &td[1]);
+
+    for i in 0..t.len() {
+        let mut r = 0;
+        for j in 0..t[i] {
+            if (t[i] - j) * j > d[i] {
+                r += 1;
+            }
+        }
+        res *= r;
+    }
+
+    res
+}
+
+pub fn part2(input: &str) -> u64 {
+    let mut res: u64 = 1;
+
+    let td: Vec<Vec<_>> = input
+        .trim_end()
+        .split('\n')
+        .map(|x| {
+            x.split(':')
+                .nth(1)
+                .unwrap()
+                .trim()
+                .replace(" ", "")
+                .split(' ')
+                .map(|y| y.parse::<u64>().unwrap())
+                .collect()
+        })
+        .collect();
+
+    assert_eq!(td.len(), 2);
+    let (t, d) = (&td[0], &td[1]);
+
+    for i in 0..t.len() {
+        let mut r = 0;
+        for j in 0..t[i] {
+            if (t[i] - j) * j > d[i] {
+                r += 1;
+            }
+        }
+        res *= r;
+    }
+
+    res
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn example_part1() {
+        let input = include_str!("../example.txt");
+        let result = part1(input);
+        assert_eq!(result, 288);
+    }
+
+    #[test]
+    fn input_part1() {
+        let input = include_str!("../input.txt");
+        let result = part1(input);
+        assert_eq!(result, 74698);
+    }
+
+    #[test]
+    fn example_part2() {
+        let input = include_str!("../example.txt");
+        let result = part2(input);
+        assert_eq!(result, 71503);
+    }
+
+    #[test]
+    fn input_part2() {
+        let input = include_str!("../input.txt");
+        let result = part2(input);
+        assert_eq!(result, 27563421);
+    }
+}
-- 
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