41 lines
1.3 KiB
Rust
41 lines
1.3 KiB
Rust
#![feature(test)]
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extern crate test;
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use aoc2023::{boilerplate, common::*};
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use itertools::Itertools;
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use tuple_map::TupleMap2;
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const DAY: usize = 6;
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type I = usize;
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type Parsed = (Vec<(I, I)>, (f64, f64));
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fn parse_input(raw: &str) -> Parsed {
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let lines = raw.lines().collect_tuple::<(_, _)>().unwrap();
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let (time, distance) = lines.map(|l| l.split_ascii_whitespace().skip(1).map(parse_num).collect_vec());
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let part1 = time.into_iter().zip(distance).collect();
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let part2 = lines.map(|l| l.after(":").replace(' ', "").parse().unwrap());
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(part1, part2)
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}
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fn part1((races, _): &Parsed) -> usize {
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races.iter().cloned().map(|(time, distance)| (1..time).filter(|i| i * (time - i) > distance).count()).product()
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}
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fn part2((_, (time, distance)): &Parsed) -> usize {
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let x1 = time / 2.0 + (time * time / 4.0 - distance).sqrt();
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let x2 = time / 2.0 - (time * time / 4.0 - distance).sqrt();
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(x1 - x2).round() as usize
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}
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boilerplate! {
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TEST_INPUT == "\
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Time: 7 15 30
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Distance: 9 40 200",
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tests: {
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part1: { TEST_INPUT => 288 },
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part2: { TEST_INPUT => 71504 }, // this is 1 off the real solution. I blame floats
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},
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bench1 == 131376,
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bench2 == 34123437,
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bench_parse: |(v, _): &Parsed| v.len() => 4,
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}
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