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authorFederico Igne <git@federicoigne.com>2021-12-06 14:33:31 +0000
committerFederico Igne <git@federicoigne.com>2021-12-06 14:33:31 +0000
commitc8734354d4d7cc4fb822f426ef9f32a787420bb4 (patch)
treee8580f77e47936ff4ac606e99e988206edb8f18b /day6
parentf9213a03a8d5efd5023c3234549d84d2805289dd (diff)
downloadaoc-c8734354d4d7cc4fb822f426ef9f32a787420bb4.tar.gz
aoc-c8734354d4d7cc4fb822f426ef9f32a787420bb4.zip
Day 6
Diffstat (limited to 'day6')
-rw-r--r--day6/Cargo.toml9
-rw-r--r--day6/resources/input.txt1
-rw-r--r--day6/src/main.rs48
3 files changed, 58 insertions, 0 deletions
diff --git a/day6/Cargo.toml b/day6/Cargo.toml
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--- /dev/null
+++ b/day6/Cargo.toml
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1[package]
2name = "day6"
3version = "0.1.0"
4authors = ["Federico Igne <git@federicoigne.com>"]
5edition = "2018"
6
7# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
8
9[dependencies]
diff --git a/day6/resources/input.txt b/day6/resources/input.txt
new file mode 100644
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+++ b/day6/resources/input.txt
@@ -0,0 +1 @@
5,1,1,5,4,2,1,2,1,2,2,1,1,1,4,2,2,4,1,1,1,1,1,4,1,1,1,1,1,5,3,1,4,1,1,1,1,1,4,1,5,1,1,1,4,1,2,2,3,1,5,1,1,5,1,1,5,4,1,1,1,4,3,1,1,1,3,1,5,5,1,1,1,1,5,3,2,1,2,3,1,5,1,1,4,1,1,2,1,5,1,1,1,1,5,4,5,1,3,1,3,3,5,5,1,3,1,5,3,1,1,4,2,3,3,1,2,4,1,1,1,1,1,1,1,2,1,1,4,1,3,2,5,2,1,1,1,4,2,1,1,1,4,2,4,1,1,1,1,4,1,3,5,5,1,2,1,3,1,1,4,1,1,1,1,2,1,1,4,2,3,1,1,1,1,1,1,1,4,5,1,1,3,1,1,2,1,1,1,5,1,1,1,1,1,3,2,1,2,4,5,1,5,4,1,1,3,1,1,5,5,1,3,1,1,1,1,4,4,2,1,2,1,1,5,1,1,4,5,1,1,1,1,1,1,1,1,1,1,3,1,1,1,1,1,4,2,1,1,1,2,5,1,4,1,1,1,4,1,1,5,4,4,3,1,1,4,5,1,1,3,5,3,1,2,5,3,4,1,3,5,4,1,3,1,5,1,4,1,1,4,2,1,1,1,3,2,1,1,4 \ No newline at end of file
diff --git a/day6/src/main.rs b/day6/src/main.rs
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+++ b/day6/src/main.rs
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1use std::fs;
2use std::path::Path;
3
4/* AOC21 Day 6: https://adventofcode.com/2021/day/6 */
5fn main() {
6 let input = Path::new("resources").join("input.txt");
7 let content = fs::read_to_string(input).expect("Unable to read input file");
8 println!("Ex1: The number of lanternfishes is {}", evolution(parse_input(&content), 80));
9 println!("Ex2: The number of lanternfishes is {}", evolution(parse_input(&content), 256));
10}
11
12fn parse_input(s: &str) -> Vec<u64> {
13 let mut lfs = vec![0;9];
14 s.split(",").for_each(|n| lfs[n.parse::<usize>().expect("Malformed input")] += 1);
15 lfs
16}
17
18fn evolution(mut lfs: Vec<u64>, days: usize) -> u64 {
19 (1..days).for_each(|i| lfs[(i+7)%9] += lfs[i%9]);
20 lfs.iter().sum()
21}
22
23#[cfg(test)]
24mod tests {
25 use super::*;
26
27 const LANTERNFISHES: &str = "3,4,3,1,2";
28
29 #[test]
30 fn input_parsing() {
31 assert_eq!(vec![0,1,1,2,1,0,0,0,0], parse_input("3,4,3,1,2"))
32 }
33
34 #[test]
35 fn evolution_18days() {
36 assert_eq!(26, evolution(parse_input(LANTERNFISHES), 18))
37 }
38
39 #[test]
40 fn evolution_80days() {
41 assert_eq!(5934, evolution(parse_input(LANTERNFISHES), 80))
42 }
43
44 #[test]
45 fn evolution_256days() {
46 assert_eq!(26984457539, evolution(parse_input(LANTERNFISHES), 256))
47 }
48}