Add day6, slowly

4 files changed, 46 insertions, 1 deletions

diff --git a/Cargo.toml b/Cargo.toml
index afacff3..56e5ff2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,2 +1,2 @@
 [workspace]
-members = ["day1", "day2", "day3", "day4"]
+members = ["day1", "day2", "day3", "day4", "day6"]
diff --git a/day6/Cargo.toml b/day6/Cargo.toml
new file mode 100644
index 0000000..89d04ae
--- /dev/null
+++ b/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/day6/input.txt b/day6/input.txt
new file mode 100644
index 0000000..de918c7
--- /dev/null
+++ b/day6/input.txt
@@ -0,0 +1 @@
+1,1,3,5,1,1,1,4,1,5,1,1,1,1,1,1,1,3,1,1,1,1,2,5,1,1,1,1,1,2,1,4,1,4,1,1,1,1,1,3,1,1,5,1,1,1,4,1,1,1,4,1,1,3,5,1,1,1,1,4,1,5,4,1,1,2,3,2,1,1,1,1,1,1,1,1,1,1,1,1,1,5,1,1,1,1,1,1,1,1,2,2,1,1,1,1,1,5,1,1,1,3,4,1,1,1,1,3,1,1,1,1,1,4,1,1,3,1,1,3,1,1,1,1,1,3,1,5,2,3,1,2,3,1,1,2,1,2,4,5,1,5,1,4,1,1,1,1,2,1,5,1,1,1,1,1,5,1,1,3,1,1,1,1,1,1,4,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,3,2,1,1,1,1,2,2,1,2,1,1,1,5,5,1,1,1,1,1,1,1,1,1,1,1,1,2,2,1,1,4,2,1,4,1,1,1,1,1,1,1,2,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,1,5,1,1,1,1,1,1,1,1,3,1,1,3,3,1,1,1,3,5,1,1,4,1,1,1,1,1,4,1,1,3,1,1,1,1,1,1,1,1,2,1,5,1,1,1,1,1,1,1,1,1,1,4,1,1,1,1
diff --git a/day6/src/main.rs b/day6/src/main.rs
new file mode 100644
index 0000000..46a148c
--- /dev/null
+++ b/day6/src/main.rs
@@ -0,0 +1,36 @@
+use std::fs::File;
+use std::io::{BufRead, BufReader};
+
+fn main() -> std::io::Result<()> {
+    let file = File::open("input.txt")?;
+    let mut reader = BufReader::new(file);
+    let mut buffer = String::new();
+
+    reader.read_line(&mut buffer)?;
+
+    let mut lanternfishes: Vec<_> = buffer
+        .trim()
+        .split(',')
+        .map(|x| x.parse::<i16>().unwrap())
+        .collect::<Vec<i16>>();
+
+    for _ in 0..80 {
+        let mut n = 0;
+        for lanternfish in lanternfishes.iter_mut() {
+            if *lanternfish == 0 {
+                *lanternfish = 6;
+                n += 1;
+            } else {
+                *lanternfish -= 1;
+            }
+        }
+
+        for _ in 0..n {
+            lanternfishes.push(8);
+        }
+    }
+
+    println!("{}", lanternfishes.len());
+
+    Ok(())
+}