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Handle diagonal lines
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@tjheslin1
tjheslin1 committed Dec 18, 2021
1 parent 0a5aff1 commit f31c1aa
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Showing 2 changed files with 103 additions and 35 deletions.
5 changes: 4 additions & 1 deletion 2021/day5/src/main.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,10 @@ fn main() {
let input = fs::read_to_string("input.txt").expect("Something went wrong reading the file");

let lines = vents::parse_input(&input[..]);
let overlap_count = vents::find_overlapping_points(&lines[..], 2);

let overlap_count = vents::find_overlapping_points(&lines[..], 2, false);
println!("overlap_count = {}", overlap_count);

let diagonal_overlap_count = vents::find_overlapping_points(&lines[..], 2, true);
println!("diagonal overlap_count = {}", diagonal_overlap_count);
}
133 changes: 99 additions & 34 deletions 2021/day5/src/vents.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,12 +5,16 @@ use itertools::Itertools;
type Point = (usize, usize);
type Line = (usize, usize, usize, usize);

pub fn find_overlapping_points(lines: &[Line], min_overlap: usize) -> usize {
pub fn find_overlapping_points(lines: &[Line], min_overlap: usize, handle_diagonal: bool) -> usize {
let mut overlaps: Vec<Point> = vec![];

for first in 0..lines.len() {
for second in first + 1..lines.len() {
overlaps.append(&mut lines_overlap(&lines[first], &lines[second]));
overlaps.append(&mut lines_overlap(
&lines[first],
&lines[second],
handle_diagonal,
));
}
}

Expand Down Expand Up @@ -39,17 +43,15 @@ pub fn parse_input(input: &str) -> Vec<Line> {
.collect::<Vec<Line>>()
}

fn lines_overlap(first: &Line, second: &Line) -> Vec<Point> {
fn lines_overlap(first: &Line, second: &Line, handle_diagonal: bool) -> Vec<Point> {
let (first_x_1, first_y_1, first_x_2, first_y_2) = *first;
let (second_x_1, second_y_1, second_x_2, second_y_2) = *second;

// if diagonal
if first_x_1 != first_x_2 && first_y_1 != first_y_2 {
if handle_diagonal == false && first_x_1 != first_x_2 && first_y_1 != first_y_2 {
return vec![];
}

// if diagonal
if second_x_1 != second_x_2 && second_y_1 != second_y_2 {
if handle_diagonal == false && second_x_1 != second_x_2 && second_y_1 != second_y_2 {
return vec![];
}

Expand All @@ -64,28 +66,26 @@ fn lines_overlap(first: &Line, second: &Line) -> Vec<Point> {
}

fn find_points(x_1: usize, y_1: usize, x_2: usize, y_2: usize) -> Vec<Point> {
let mut points: Vec<Point> = vec![];

let min_x = cmp::min(x_1, x_2);
let max_x = cmp::max(x_1, x_2);

let min_y = cmp::min(y_1, y_2);
let max_y = cmp::max(y_1, y_2);

let mut x = min_x;
let mut y = min_y;
while x <= max_x {
while y <= max_y {
points.push((x, y));

y += 1;
}

x += 1;
y = min_y;
}

points
let x_length = i32::abs((x_1 as i32) - (x_2 as i32)) as usize;
let y_length = i32::abs((y_1 as i32) - (y_2 as i32)) as usize;

let x_range = match x_length {
0 => vec![x_1; y_length + 1],
_ if x_1 <= x_2 => (x_1..=x_2).collect::<Vec<usize>>(),
_ => (x_2..=x_1).rev().collect::<Vec<usize>>(),
};

let y_range = match y_length {
0 => vec![y_1; x_length + 1],
_ if y_1 <= y_2 => (y_1..=y_2).collect::<Vec<usize>>(),
_ => (y_2..=y_1).rev().collect::<Vec<usize>>(),
};

x_range
.iter()
.zip(y_range.iter())
.map(|(x, y)| (*x, *y))
.collect::<Vec<Point>>()
}

#[cfg(test)]
Expand Down Expand Up @@ -138,11 +138,31 @@ mod tests {
(5, 5, 8, 2),
];

let actual_num_overlapping_points = find_overlapping_points(&input_points[..], 2);
let actual_num_overlapping_points = find_overlapping_points(&input_points[..], 2, false);

assert_eq!(actual_num_overlapping_points, 5);
}

#[test]
fn test_find_overlapping_points_diagonal_example() {
let input_points = vec![
(0, 9, 5, 9),
(8, 0, 0, 8),
(9, 4, 3, 4),
(2, 2, 2, 1),
(7, 0, 7, 4),
(6, 4, 2, 0),
(0, 9, 2, 9),
(3, 4, 1, 4),
(0, 0, 8, 8),
(5, 5, 8, 2),
];

let actual_num_overlapping_points = find_overlapping_points(&input_points[..], 2, true);

assert_eq!(actual_num_overlapping_points, 12);
}

/*
1.........
1.........
Expand Down Expand Up @@ -171,6 +191,34 @@ mod tests {
assert_eq!(actual, expected);
}

/*
1.........
.1........
..1.......
..........
*/
#[test]
fn test_find_points_diagonal() {
let actual = find_points(0, 0, 2, 2);
let expected = vec![(0, 0), (1, 1), (2, 2)];

assert_eq!(actual, expected);
}

/*
..1.......
.1........
1.........
..........
*/
#[test]
fn test_find_points_diagonal_back() {
let actual = find_points(2, 0, 0, 2);
let expected = vec![(2, 0), (1, 1), (0, 2)];

assert_eq!(actual, expected);
}

/*
1.1.......
1.1.......
Expand All @@ -182,7 +230,7 @@ mod tests {
let first = (0, 0, 0, 2);
let second = (2, 0, 2, 2);

let actual = lines_overlap(&first, &second);
let actual = lines_overlap(&first, &second, false);
let expected = vec![];

assert_eq!(actual, expected);
Expand All @@ -199,7 +247,7 @@ mod tests {
let first = (0, 0, 0, 2);
let second = (0, 1, 3, 1);

let actual = lines_overlap(&first, &second);
let actual = lines_overlap(&first, &second, false);
let expected = vec![(0, 1)];

assert_eq!(actual, expected);
Expand All @@ -216,7 +264,7 @@ mod tests {
let first = (0, 0, 2, 0);
let second = (2, 0, 2, 2);

let actual = lines_overlap(&first, &second);
let actual = lines_overlap(&first, &second, false);
let expected = vec![(2, 0)];

assert_eq!(actual, expected);
Expand All @@ -233,9 +281,26 @@ mod tests {
let first = (2, 0, 2, 2);
let second = (2, 0, 2, 1);

let actual = lines_overlap(&first, &second);
let actual = lines_overlap(&first, &second, false);
let expected = vec![(2, 0), ((2, 1))];

assert_eq!(actual, expected);
}

/*
1.1.......
.2........
1.1.......
..........
*/
#[test]
fn test_do_lines_overlap_diagonals() {
let first = (2, 0, 0, 2);
let second = (0, 0, 2, 2);

let actual = lines_overlap(&first, &second, true);
let expected = vec![(1, 1)];

assert_eq!(actual, expected);
}
}

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