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day-24 done

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This commit is contained in:
Dylan Thies
2023-12-28 14:53:11 -05:00
parent 6c8b4058fe
commit e034f6b859
4 changed files with 293 additions and 15 deletions
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38
2023/day-24/src/part1.rs
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@@ -5,8 +5,9 @@ use nom::{
bytes::complete::tag,
character::complete,
multi::separated_list1,
number,
sequence::{separated_pair, tuple},
IResult, Parser, number,
IResult, Parser,
};
use itertools::Itertools;
@@ -23,34 +24,52 @@ impl Stones {
// (y_n - y_1)/v_y1 = (x_n - x_1)/v_x1
// y_n = v_y1 * (x_n -x_1)/v_x1 + y_1
// (v_y1/v_x1) * x_n - x_1 * (v_y1/v_x1) + y_1 = (v_y2/v_x2) * x_n -x_2 * (v_y2/v_x2) + y_2
// x_n * ((v_y1/v_x1) - (v_y2/v_x2)) = x_1 * (v_y1/v_x1) - x_2 * (v_y2/v_x2) + y_2 - y_1
// x_n * ((v_y1/v_x1) - (v_y2/v_x2)) = x_1 * (v_y1/v_x1) - x_2 * (v_y2/v_x2) + y_2 - y_1
// x1 + v1 *t == x2 + v2*t
// (x1-x2)/(v2-v1) = t
let slope1 = self.velocity.y / self.velocity.x;
let slope2 = other.velocity.y / other.velocity.x;
let denom = slope1 - slope2;
let x = (self.start.x *slope1 -other.start.x *slope2 + other.start.y - self.start.y) / denom;
let x =
(self.start.x * slope1 - other.start.x * slope2 + other.start.y - self.start.y) / denom;
let y = slope1 * (x - self.start.x) + self.start.y;
if !x.is_finite() || !y.is_finite() {
return None;
}
let t1 = (x - self.start.x) / self.velocity.x;
let t2 = (x - other.start.x) / other.velocity.x;
if t1 < 0.0 || t2 < 0.0{
if t1 < 0.0 || t2 < 0.0 {
return None;
}
Some(DVec3::new(x, y, 0.0))
}
}
/// day 24 part 1 of aoc 2023
///
/// # Arguments
/// - input the input for today's puzzle
///
/// # Panics
/// panics whne it cannot parse the input OR when ever the number of game numbers is greater than
#[must_use]
pub fn part1(input: &str, min:f64, max:f64) -> String {
pub fn part1(input: &str, min: f64, max: f64) -> String {
let (_, stones) = parse_input(input).expect("Aoc should have valid input");
stones.iter().combinations(2)
stones
.iter()
.combinations(2)
.filter_map(|pair| {
let [a,b] = pair[..] else { return None};
a.cross(b).and_then(|cross_position| (cross_position.x <= max && cross_position.y <= max && cross_position.x >= min && cross_position.y >= min).then_some(cross_position) )
}).count().to_string()
let [a, b] = pair[..] else { return None };
a.cross(b).and_then(|cross_position| {
(cross_position.x <= max
&& cross_position.y <= max
&& cross_position.x >= min
&& cross_position.y >= min)
.then_some(cross_position)
})
})
.count()
.to_string()
}
fn parse_tuple(input: &str) -> IResult<&str, DVec3> {
@@ -90,4 +109,3 @@ mod test {
assert_eq!(result, "2".to_string());
}
}