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author | June McEnroe <june@causal.agency> | 2017-12-06 00:28:02 -0500 |
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committer | June McEnroe <june@causal.agency> | 2020-11-22 00:14:25 -0500 |
commit | 037c2a4d3ce3db556b5acb971a8a234789d6a179 (patch) | |
tree | 937cf56737a31a302fc7e8e0799efff7793f8927 /2017/src | |
parent | Day 6 (diff) | |
download | aoc-037c2a4d3ce3db556b5acb971a8a234789d6a179.tar.gz aoc-037c2a4d3ce3db556b5acb971a8a234789d6a179.zip |
Day 6, part 2
Diffstat (limited to '')
-rw-r--r-- | 2017/src/bin/day06.rs | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/2017/src/bin/day06.rs b/2017/src/bin/day06.rs index dbc8d07..509e576 100644 --- a/2017/src/bin/day06.rs +++ b/2017/src/bin/day06.rs @@ -1,16 +1,17 @@ -use std::collections::HashSet; +use std::collections::hash_map::{Entry, HashMap}; use std::io::{self, Read}; -fn solve1(input: &str) -> u32 { +fn solve(input: &str) -> (u32, u32) { let mut banks: Vec<u32> = input.split_whitespace() .map(str::parse) .map(Result::unwrap) .collect(); - let mut states = HashSet::new(); + let mut states = HashMap::new(); for cycle in 0.. { - if !states.insert(banks.clone()) { - return cycle; + match states.entry(banks.clone()) { + Entry::Occupied(e) => return (cycle, cycle - e.get()), + Entry::Vacant(e) => { e.insert(cycle); }, } let (index, mut blocks) = banks.iter() @@ -32,14 +33,28 @@ fn solve1(input: &str) -> u32 { unreachable!() } +fn solve1(input: &str) -> u32 { + solve(input).0 +} + +fn solve2(input: &str) -> u32 { + solve(input).1 +} + fn main() { let mut input = String::new(); io::stdin().read_to_string(&mut input).unwrap(); println!("Part 1: {}", solve1(input.trim())); + println!("Part 2: {}", solve2(input.trim())); } #[test] fn part1() { assert_eq!(5, solve1("0 2 7 0")); } + +#[test] +fn part2() { + assert_eq!(4, solve2("0 2 7 0")); +} |