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use std::{collections::HashMap, marker::PhantomData};
#[derive(Debug)]
struct Race<State = Part1> {
times: Vec<u64>,
distances: Vec<u64>,
state: std::marker::PhantomData<State>,
}
struct Part1;
struct Part2;
impl From<&str> for Race<Part1> {
fn from(value: &str) -> Self {
let (times, distances) = value.split_once("\n").unwrap();
let (_, times) = times.split_once(':').unwrap();
let (_, distances) = distances.split_once(':').unwrap();
let times = times
.split_whitespace()
.map(|x| x.parse::<u64>().unwrap())
.collect::<Vec<_>>();
let distances = distances
.split_whitespace()
.map(|x| x.parse::<u64>().unwrap())
.collect::<Vec<_>>();
Self {
times,
distances,
state: PhantomData::<Part1>,
}
}
}
impl From<&str> for Race<Part2> {
fn from(value: &str) -> Self {
let (times, distances) = value.split_once("\n").unwrap();
let (_, times) = times.split_once(':').unwrap();
let (_, distances) = distances.split_once(':').unwrap();
let times = times
.chars()
.filter(|ch| ch.is_digit(10))
.collect::<String>()
.parse::<u64>()
.unwrap();
let distances = distances
.chars()
.filter(|ch| ch.is_digit(10))
.collect::<String>()
.parse::<u64>()
.unwrap();
Self {
times: vec![times],
distances: vec![distances],
state: PhantomData::<Part2>,
}
}
}
fn solve_part_one(data: &str) -> u64 {
let race: Race<Part1> = Race::from(data);
let mut cnt = 0;
let mut ans = 1;
for (i, _) in race.times.iter().enumerate() {
for t in 0..=race.times[i] {
if (race.times[i] - t) * t > race.distances[i] {
cnt += 1;
}
}
ans *= cnt;
cnt = 0;
}
ans
}
fn solve_part_two(data: &str) -> u64 {
let race: Race<Part2> = Race::from(data);
let mut ans = 0;
for t in 0..=race.times[0] {
if (race.times[0] - t) * t > race.distances[0] {
ans += 1;
}
}
ans
}
fn main() {
let test = include_str!("../input/day6.test");
let prod = include_str!("../input/day6.prod");
println!("part_1 test: {:?}", solve_part_one(test));
println!("part_1 prod {:?}", solve_part_one(prod));
println!("part_2 test: {:?}", solve_part_two(test));
println!("part_2 prod {:?}", solve_part_two(prod));
}
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