72 lines
1.7 KiB
Rust
72 lines
1.7 KiB
Rust
use std::fs::read_to_string;
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use itertools::Itertools;
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pub fn day_main() {
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let input = read_to_string("input/day02.txt").unwrap();
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println!(" part1: {}", part1(&input));
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println!(" part2: {}", part2(&input));
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}
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fn part1(input: &str) -> usize {
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input
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.lines()
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.map(|line| {
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line.split_whitespace()
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.map(|s| s.parse::<i32>().unwrap())
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.collect_vec()
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})
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.filter(|report: &Vec<i32>| is_safe(report))
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.count()
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}
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fn part2(input: &str) -> usize {
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input
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.lines()
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.map(|line| {
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line.split_whitespace()
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.map(|s| s.parse::<i32>().unwrap())
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.collect_vec()
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})
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.filter(|report: &Vec<i32>| {
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(0..report.len()).any(|del| {
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let without = report
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.iter()
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.enumerate()
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.filter_map(|(i, e)| if del != i { Some(*e) } else { None })
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.collect_vec();
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is_safe(&without)
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})
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})
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.count()
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}
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fn is_safe(report: &[i32]) -> bool {
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let pairs = report
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.windows(2)
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.map(|window| window[1] - window[0])
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.collect_vec();
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let steepest_slope = pairs.iter().map(|x| x.abs()).max().unwrap();
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let lowest_slope = pairs.iter().map(|x| x.abs()).min().unwrap();
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let same_sign = pairs.iter().map(|x| x.signum()).unique().count() == 1;
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steepest_slope <= 3 && lowest_slope >= 1 && same_sign
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}
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// fn part2(input: &str) -> Int {
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// 0
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// }
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#[cfg(test)]
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mod test {
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#[test]
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fn part1() {
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let input = r"7 6 4 2 1
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1 2 7 8 9
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9 7 6 2 1
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1 3 2 4 5
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8 6 4 4 1
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1 3 6 7 9";
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assert_eq!(2, super::part1(input));
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}
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}
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