53 lines
1.4 KiB
Rust
53 lines
1.4 KiB
Rust
#![feature(test)]
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extern crate test;
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use aoc2021::common::*;
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const DAY: usize = 6;
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const FERTILITY_CYCLE: usize = 7;
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const DAYS_TO_FERTILITY: usize = 2;
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type Parsed = Vec<usize>;
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fn parse_input(raw: &str) -> Parsed {
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parse_nums_comma(raw)
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}
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fn simulate<const LIMIT: usize>(parsed: &Parsed) -> usize {
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let mut fish_from_day = [1; LIMIT];
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for i in (0..LIMIT).rev() {
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let mut next_child = i + FERTILITY_CYCLE + DAYS_TO_FERTILITY;
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while next_child < LIMIT {
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fish_from_day[i] += fish_from_day[next_child];
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next_child += FERTILITY_CYCLE;
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}
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}
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let mut adult_from_day = vec![1; LIMIT];
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for i in (0..LIMIT).rev() {
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let mut child_at = i + FERTILITY_CYCLE;
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while child_at < LIMIT {
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adult_from_day[i] += fish_from_day[child_at];
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child_at += FERTILITY_CYCLE;
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}
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}
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parsed.iter().map(|&i| adult_from_day[i] + fish_from_day[i]).sum()
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}
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fn main() {
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let input = parse_input(&read_file(DAY));
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println!("Part 1: {}", simulate::<80>(&input));
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println!("Part 2: {}", simulate::<256>(&input));
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use aoc2021::*;
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const TEST_INPUT: &str = "3,4,3,1,2";
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test!(simulate<80>() == 5934);
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test!(simulate<256>() == 26984457539);
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bench!(simulate<80>() == 365862);
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bench!(simulate<256>() == 1653250886439);
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bench_input!(Vec::len => 300);
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}
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