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day17 part2

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This commit is contained in:
Glenn Griffin 2020-12-18 16:08:14 -08:00
parent 3a7cada1f9
commit 9e2e317f8d
1 changed files with 24 additions and 14 deletions
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32
src/day17.rs
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@ -8,7 +8,7 @@ fn solve_d17_p1(input: &str) -> usize {
for (x, _) in line.as_bytes().iter().copied().enumerate().filter(|&(_, byte)| {
byte == b'#'
}) {
world.insert((x as isize, y as isize, 0isize));
world.insert((x as isize, y as isize, 0isize, 0isize));
}
}
for _ in 0 .. 6 {
@ -17,19 +17,21 @@ fn solve_d17_p1(input: &str) -> usize {
world.len()
}
fn neighbors(world: &HashSet<(isize, isize, isize)>, (x, y, z): (isize, isize, isize)) -> usize {
fn neighbors(world: &HashSet<(isize, isize, isize, isize)>, (x, y, z, w): (isize, isize, isize, isize)) -> usize {
let mut count = 0;
for xa in x-1..=x+1 {
for ya in y-1..=y+1 {
for za in z-1..=z+1 {
count += world.contains(&(xa, ya, za)) as usize;
for wa in w-1..=w+1 {
count += world.contains(&(xa, ya, za, wa)) as usize;
}
}
}
count - world.contains(&(x, y, z)) as usize
}
count - world.contains(&(x, y, z, w)) as usize
}
fn step(world: HashSet<(isize, isize, isize)>) -> HashSet<(isize, isize, isize)> {
fn step(world: HashSet<(isize, isize, isize, isize)>) -> HashSet<(isize, isize, isize, isize)> {
struct MinMax {
x_min: isize,
x_max: isize,
@ -37,9 +39,11 @@ fn step(world: HashSet<(isize, isize, isize)>) -> HashSet<(isize, isize, isize)>
y_max: isize,
z_min: isize,
z_max: isize,
w_min: isize,
w_max: isize,
}
let MinMax{
x_min, x_max, y_min, y_max, z_min, z_max,
x_min, x_max, y_min, y_max, z_min, z_max, w_min, w_max,
} = world.iter().fold(MinMax{
x_min: isize::MAX,
x_max: isize::MIN,
@ -47,7 +51,9 @@ fn step(world: HashSet<(isize, isize, isize)>) -> HashSet<(isize, isize, isize)>
y_max: isize::MIN,
z_min: isize::MAX,
z_max: isize::MIN,
}, |minmax, &(x, y, z)| {
w_min: isize::MAX,
w_max: isize::MIN,
}, |minmax, &(x, y, z, w)| {
MinMax{
x_min: std::cmp::min(minmax.x_min, x),
x_max: std::cmp::max(minmax.x_max, x),
@ -55,19 +61,23 @@ fn step(world: HashSet<(isize, isize, isize)>) -> HashSet<(isize, isize, isize)>
y_max: std::cmp::max(minmax.y_max, y),
z_min: std::cmp::min(minmax.z_min, z),
z_max: std::cmp::max(minmax.z_max, z),
w_min: std::cmp::min(minmax.w_min, w),
w_max: std::cmp::max(minmax.w_max, w),
}
});
let mut new_world = HashSet::new();
for x in x_min -1 ..= x_max + 1 {
for y in y_min -1 ..= y_max + 1 {
for z in z_min -1 ..= z_max + 1 {
let active = world.contains(&(x, y, z));
let n = neighbors(&world, (x, y, z));
for w in w_min -1 ..= w_max + 1 {
let active = world.contains(&(x, y, z, w));
let n = neighbors(&world, (x, y, z, w));
if active && (n == 2 || n == 3) {
new_world.insert((x, y, z));
new_world.insert((x, y, z, w));
}
if !active && n == 3 {
new_world.insert((x, y, z));
new_world.insert((x, y, z, w));
}
}
}
}