From 774843c3e7bbf2a9bfdd31d9d4197b623d47d0ce Mon Sep 17 00:00:00 2001
From: LongHairedHacker <sebastian@sebastians-site.de>
Date: Tue, 7 Dec 2021 15:23:45 +0100
Subject: [PATCH] Solved Day 6

---
 inputs/day6.txt   |  1 +
 inputs/sample.txt | 11 +---------
 src/bin/day6.rs   | 51 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 10 deletions(-)
 create mode 100644 inputs/day6.txt
 create mode 100644 src/bin/day6.rs

diff --git a/inputs/day6.txt b/inputs/day6.txt
new file mode 100644
index 0000000..aa0969e
--- /dev/null
+++ b/inputs/day6.txt
@@ -0,0 +1 @@
+2,3,1,3,4,4,1,5,2,3,1,1,4,5,5,3,5,5,4,1,2,1,1,1,1,1,1,4,1,1,1,4,1,3,1,4,1,1,4,1,3,4,5,1,1,5,3,4,3,4,1,5,1,3,1,1,1,3,5,3,2,3,1,5,2,2,1,1,4,1,1,2,2,2,2,3,2,1,2,5,4,1,1,1,5,5,3,1,3,2,2,2,5,1,5,2,4,1,1,3,3,5,2,3,1,2,1,5,1,4,3,5,2,1,5,3,4,4,5,3,1,2,4,3,4,1,3,1,1,2,5,4,3,5,3,2,1,4,1,4,4,2,3,1,1,2,1,1,3,3,3,1,1,2,2,1,1,1,5,1,5,1,4,5,1,5,2,4,3,1,1,3,2,2,1,4,3,1,1,1,3,3,3,4,5,2,3,3,1,3,1,4,1,1,1,2,5,1,4,1,2,4,5,4,1,5,1,5,5,1,5,5,2,5,5,1,4,5,1,1,3,2,5,5,5,4,3,2,5,4,1,1,2,4,4,1,1,1,3,2,1,1,2,1,2,2,3,4,5,4,1,4,5,1,1,5,5,1,4,1,4,4,1,5,3,1,4,3,5,3,1,3,1,4,2,4,5,1,4,1,2,4,1,2,5,1,1,5,1,1,3,1,1,2,3,4,2,4,3,1
diff --git a/inputs/sample.txt b/inputs/sample.txt
index b258f68..55129f1 100644
--- a/inputs/sample.txt
+++ b/inputs/sample.txt
@@ -1,10 +1 @@
-0,9 -> 5,9
-8,0 -> 0,8
-9,4 -> 3,4
-2,2 -> 2,1
-7,0 -> 7,4
-6,4 -> 2,0
-0,9 -> 2,9
-3,4 -> 1,4
-0,0 -> 8,8
-5,5 -> 8,2
+3,4,3,1,2
diff --git a/src/bin/day6.rs b/src/bin/day6.rs
new file mode 100644
index 0000000..c2ab31d
--- /dev/null
+++ b/src/bin/day6.rs
@@ -0,0 +1,51 @@
+use std::error::Error;
+use std::fs::File;
+use std::io::{self, BufRead};
+use std::vec::Vec;
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let file = File::open("inputs/day6.txt")?;
+    let mut fishes: Vec<u64> = io::BufReader::new(file)
+        .lines()
+        .nth(0)
+        .unwrap()
+        .unwrap()
+        .split(",")
+        .map(|f| f.parse().unwrap())
+        .collect();
+
+    let mut answer1 = 0;
+    let mut answer2 = 0;
+
+    let mut population: Vec<u64> = Vec::new();
+    population.resize(9, 0);
+    for fish in fishes {
+        population[fish as usize] += 1;
+    }
+
+    for day in 0..256 {
+        let mut next_population: Vec<u64> = Vec::new();
+        next_population.resize(9, 0);
+
+        next_population[6] = population[0];
+        next_population[8] = population[0];
+
+        for i in 1..9 {
+            next_population[i - 1] += population[i];
+        }
+
+        population = next_population;
+
+        if day == 18 {
+            answer1 = population.iter().fold(0, |a, b| a + b);
+        }
+    }
+
+    answer2 = population.iter().fold(0, |a, b| a + b);
+
+    println!("Answer1: {}", answer1);
+
+    println!("Answer2: {}", answer2);
+
+    Ok(())
+}