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author | June McEnroe <june@causal.agency> | 2017-12-06 00:21:27 -0500 |
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committer | June McEnroe <june@causal.agency> | 2020-11-22 00:14:25 -0500 |
commit | de6032fd058b51d623a09e687c55e138358d3226 (patch) | |
tree | 250d0fc329d876437adc13b17743a9775d9f50e2 /2017/src/bin | |
parent | Day 5, part 2 (diff) | |
download | aoc-de6032fd058b51d623a09e687c55e138358d3226.tar.gz aoc-de6032fd058b51d623a09e687c55e138358d3226.zip |
Day 6
Diffstat (limited to '')
-rw-r--r-- | 2017/src/bin/day06.rs | 45 |
1 files changed, 45 insertions, 0 deletions
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<u32> = 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")); +} |