From 2a92665f761bc1da4248a45542be8a6430cfa1d4 Mon Sep 17 00:00:00 2001 From: Curtis McEnroe Date: Wed, 6 Dec 2017 00:21:27 -0500 Subject: Day 6 --- 2017/src/bin/day06.rs | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 2017/src/bin/day06.rs (limited to '2017/src') diff --git a/2017/src/bin/day06.rs b/2017/src/bin/day06.rs new file mode 100644 index 0000000..dbc8d07 --- /dev/null +++ b/2017/src/bin/day06.rs @@ -0,0 +1,45 @@ +use std::collections::HashSet; +use std::io::{self, Read}; + +fn solve1(input: &str) -> u32 { + let mut banks: Vec = input.split_whitespace() + .map(str::parse) + .map(Result::unwrap) + .collect(); + let mut states = HashSet::new(); + + for cycle in 0.. { + if !states.insert(banks.clone()) { + return cycle; + } + + let (index, mut blocks) = banks.iter() + .cloned() + .enumerate() + .rev() + .max_by_key(|&(_, n)| n) + .unwrap(); + + banks[index] = 0; + for bank in (0..banks.len()).cycle().skip(index + 1) { + banks[bank] += 1; + blocks -= 1; + if blocks == 0 { + break; + } + } + } + unreachable!() +} + +fn main() { + let mut input = String::new(); + io::stdin().read_to_string(&mut input).unwrap(); + + println!("Part 1: {}", solve1(input.trim())); +} + +#[test] +fn part1() { + assert_eq!(5, solve1("0 2 7 0")); +} -- cgit 1.4.1