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#![allow(non_snake_case)]
use std::fs::File;
use std::io::Read;
fn get_opts(t: u64, d: u64) -> u64 {
let t = t as f64;
let d = d as f64;
let D = f64::sqrt((t * t - 4. * d) as f64);
let x1 = ((-t - D) / 2.).floor();
let x2 = ((-t + D) / 2.).floor();
(x2 - x1) as u64
}
fn main() {
// let filename = "in/day06.ref";
let filename = "in/day06.pzl";
let mut f = File::open(filename).expect("cannot open file");
let mut content = String::new();
f.read_to_string(&mut content).expect("cannot read file");
let mut lines = content.trim_end().split('\n');
let parse1 = |l: &str| {
l.split_once(":")
.unwrap()
.1
.split(" ")
.filter_map(|x| x.parse::<u64>().ok())
.collect::<Vec<u64>>()
};
let time = parse1(lines.next().unwrap());
let dist = parse1(lines.next().unwrap());
let res1 = time
.into_iter()
.zip(dist.into_iter())
.map(|(t, d)| get_opts(t, d))
.fold(1, |acc, x| acc * x);
let mut lines = content.trim_end().split('\n');
let parse2 = |l: &str| {
l.split_once(":")
.unwrap()
.1
.split_whitespace()
.collect::<Vec<_>>()
.join("")
.parse()
.unwrap()
};
let time = parse2(lines.next().unwrap());
let dist = parse2(lines.next().unwrap());
let res2 = get_opts(time, dist);
println!("res1: {}", res1);
println!("res2: {}", res2);
assert_eq!(res1, 220320);
assert_eq!(res2, 34454850);
}
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