92 lines
2.4 KiB
Rust
92 lines
2.4 KiB
Rust
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#![feature(test)]
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use std::{collections::BinaryHeap, fs::read_to_string};
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fn main() {
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let input = read_to_string("input.txt").expect("need input file");
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let (max, top3) = initial(&input);
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println!("{max}, {top3}");
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let (max, top3) = idiomatic(&input);
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println!("{max}, {top3}");
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}
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fn idiomatic(input: &str) -> (u32, u32) {
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let mut sums: BinaryHeap<_> = input
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.split_terminator("\n\n")
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.map(|block| {
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block
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.split_terminator('\n')
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.map(|line| line.parse::<u32>().unwrap_or_default())
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.sum()
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})
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.collect();
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let max = sums.pop().unwrap_or_default();
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let top3 = max + sums.pop().unwrap_or_default() + sums.pop().unwrap_or_default();
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(max, top3)
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}
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fn initial(input: &str) -> (u32, u32) {
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let numbers = input.split_terminator('\n').map(|s| s.parse::<u32>().ok());
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let mut elves = vec![0];
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for number in numbers {
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match number {
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Some(ration) => {
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*elves.last_mut().unwrap() += ration;
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}
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None => elves.push(0),
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}
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}
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let (index, max) = elves.iter().enumerate().max_by_key(|(_, v)| **v).unwrap();
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let mut elves = elves.clone();
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elves.remove(index);
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let (index, second) = elves.iter().enumerate().max_by_key(|(_, v)| **v).unwrap();
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let mut elves = elves.clone();
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elves.remove(index);
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let third = elves.iter().max().unwrap();
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let top3 = max + second + third;
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(*max, top3)
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}
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#[cfg(test)]
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mod tests {
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use std::{
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fs::File,
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io::{BufRead, BufReader},
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};
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use super::*;
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extern crate test;
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use test::Bencher;
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#[bench]
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fn bench_initial(b: &mut Bencher) {
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let input = read_to_string("input.txt").expect("need input file");
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b.iter(|| initial(&input));
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}
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#[bench]
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fn bench_idiomatic(b: &mut Bencher) {
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let input = read_to_string("input.txt").expect("need input file");
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b.iter(|| idiomatic(&input));
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}
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#[bench]
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fn bench_read_string(b: &mut Bencher) {
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b.iter(|| {
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read_to_string("input.txt")
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.unwrap()
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.split_terminator('\n')
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.for_each(drop);
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});
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}
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#[bench]
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fn bench_lines(b: &mut Bencher) {
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b.iter(|| {
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BufReader::new(File::open("input.txt").unwrap())
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.lines()
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.for_each(drop);
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});
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}
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}
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