advent-of-code/2023/src/bin/day01.rs

65 lines
1.5 KiB
Rust

#![feature(test)]
extern crate test;
use aoc2023::{boilerplate, common::*};
const DAY: usize = 1;
type Parsed<'a> = Vec<&'a str>;
fn parse_input(raw: &str) -> Parsed<'_> {
raw.lines().collect()
}
fn part1(parsed: &Parsed) -> usize {
parsed
.iter()
.map(|l| {
let l: Vec<_> = l.bytes().filter_map(digit_as_usize).collect();
l[0] * 10 + l.last().unwrap()
})
.sum()
}
const DIGITS: [&str; 9] = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine"];
fn digit_as_usize(b: u8) -> Option<usize> {
b.is_ascii_digit().then_some((b - b'0') as usize)
}
fn find_digit(s: &str) -> Option<usize> {
digit_as_usize(s.as_bytes()[0]).or_else(|| DIGITS.iter().position(|d| s.starts_with(d)).map(|x| x + 1))
}
fn part2(parsed: &Parsed) -> usize {
parsed
.iter()
.map(|l| {
let first = (0..l.len()).find_map(|s| find_digit(&l[s..])).unwrap();
let last = (0..l.len()).rev().find_map(|s| find_digit(&l[s..])).unwrap();
first * 10 + last
})
.sum()
}
#[cfg(test)]
const TEST_INPUT_2: &str = "two1nine
eightwothree
abcone2threexyz
xtwone3four
4nineeightseven2
zoneight234
7pqrstsixteen";
boilerplate! {
TEST_INPUT == "1abc2
pqr3stu8vwx
a1b2c3d4e5f
treb7uchet",
tests: {
part1: { TEST_INPUT => 142 },
part2: { TEST_INPUT_2 => 281 },
},
bench1 == 54916,
bench2 == 54728,
bench_parse: Vec::len => 1000,
}