73 lines
1.2 KiB
Rust
73 lines
1.2 KiB
Rust
use aoc_runner_derive::{aoc, aoc_generator};
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use itertools::Itertools;
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const PREAMBLE_LEN: usize = 5;
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#[aoc_generator(day9)]
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fn parse(input: &str) -> Vec<u64> {
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input.lines().map(str::parse).map(Result::unwrap).collect_vec()
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}
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#[aoc(day9, part1)]
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fn part1(input: &Vec<u64>) -> u64 {
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for i in PREAMBLE_LEN..input.len() {
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if let None = input[i - PREAMBLE_LEN..i]
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.iter()
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.combinations(2)
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.find(|x| x.iter().cloned().sum::<u64>() == input[i]) {
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return input[i];
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}
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}
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unreachable!()
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}
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#[aoc(day9, part2)]
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fn part2(input: &Vec<u64>) -> u64 {
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let to_find = part1(input);
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for len in 2..input.len() {
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if let Some(nums) = input
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.windows(len)
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.find(|x| x.iter().cloned().sum::<u64>() == to_find) {
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return nums.iter().min().unwrap() + nums.iter().max().unwrap();
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}
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}
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unreachable!()
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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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const EX: &str = r"35
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20
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15
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25
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47
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40
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62
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55
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65
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95
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102
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117
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150
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182
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127
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219
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299
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277
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309
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576";
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#[test]
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fn part1_example() {
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assert_eq!(part1(&parse(EX)), 127);
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}
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#[test]
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fn part2_example() {
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assert_eq!(part2(&parse(EX)), 62);
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}
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} |