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Day 8 Checkpoint
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Marshall Davis committed Dec 9, 2024
1 parent f0472a3 commit e0810c1
Showing 1 changed file with 87 additions and 27 deletions.
114 changes: 87 additions & 27 deletions 2024/08/puzzle.php
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ public function slope(Coordinate $destination): mixed
try {
return ($destination->row - $this->row) / ($destination->column - $this->column);
} catch (DivisionByZeroError) {
return null;
return ($destination->row - $this->row) > 0 ? '-INF' : 'INF';
}
}

Expand All @@ -26,6 +26,8 @@ public function __toString(): string
}
}

assert((new Coordinate(20, 0))->slope(new Coordinate(1, 0)) === "INF");

/**
* @mixin Coordinate
*/
Expand Down Expand Up @@ -138,9 +140,10 @@ public function visualize(): string
$representation = '';
foreach ($this->grid as $x => $row) {
foreach ($row as $y => $cell) {
/** @var AntiNode $antinode */
foreach ($this->antinodes as $antinode) {
if ((string) $antinode === "$y-$x") {
$representation .= '#';
$representation .= $antinode->broadcasting()[0];
continue 2;
}
}
Expand Down Expand Up @@ -185,34 +188,91 @@ private function findAntinodes(): self
foreach ($this->antennas as $originator) {
echo "\tFor originator {$originator}\n";
/** @var Antenna $relay */
foreach (array_filter($this->antennas, fn(Antenna $antenna
) => ($antenna->identifier() !== $originator->identifier()) && ($antenna->frequency === $originator->frequency)) as $relay) {
foreach ($this->grid as $row => $entries) {
foreach ($entries as $column => $cell) {
$position = new Coordinate($row, $column);
if (
$relay->row !== $originator->row
&& $relay->column !== $originator->column
&& $position->slope($originator->coordinate) !== $originator->slope($relay->coordinate)
) {
continue;
foreach (
array_filter(
$this->antennas,
fn(Antenna $antenna) => ($antenna->identifier() !== $originator->identifier())
&& ($antenna->frequency === $originator->frequency)
) as $relay) {
$distance = $originator->distanceTo($relay->coordinate);
$slope = $originator->slope($relay->coordinate);
if ($slope === 'INF') {
/**
* This is a vertical line; INF means that the relay is "above" the originator.
* Therefor there is a node at ($originator->row + $distance, $originator->column) "below"
* the originator and one at ($relay->row - $distance, $relay->column)
*/
if ($this->contains(($lowerNode = new AntiNode(new Coordinate($originator->row + $distance, $originator->column), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $lowerNode;
}
if ($this->contains(($upperNode = new AntiNode(new Coordinate($relay->row - $distance, $relay->column), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $upperNode;
}
continue;
}
if ($slope === '-INF') {
/**
* This is a vertical line; INF means that the relay is "below" the originator.
* Therefor there is a node at ($relay->row + $distance, $relay->column) "below"
* the relay and one at ($originator->row - $distance, $originator->column)
*/
if ($this->contains(($lowerNode = new AntiNode(new Coordinate($relay->row + $distance, $relay->column), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $lowerNode;
}
if ($this->contains(($upperNode = new AntiNode(new Coordinate($originator->row - $distance, $originator->column), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $upperNode;
}
continue;
}
if ($slope === 0) {
/**
* This is a horizontal line. The "rightmost" antenna can be determined by comparing the columns;
* to the "right"" of this is by the distance one node. To the "left" of the other is another.
*/
if ($relay->column > $originator->column) {
// The relay is to the "right".
if ($this->contains(($rightNode = new AntiNode(new Coordinate($relay->row, $relay->column+$distance), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $rightNode;
}
$distances = [
$position->distanceTo($originator->coordinate),
$position->distanceTo($relay->coordinate),
];

if (in_array(0, $distances)) {
continue;
if ($this->contains(($leftNode = new AntiNode(new Coordinate($originator->row, $originator->column - $distance), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $leftNode;
}

sort($distances);

if ((($distances[1] / $distances[0]) === 2) && empty(array_filter($this->antinodes,
fn(AntiNode $node) => (string) $node === (string) $position))) {
$this->antinodes[] = new AntiNode($position, [$originator->frequency]);
} else {
if ($this->contains(($rightNode = new AntiNode(new Coordinate($originator->row, $originator->column+$distance), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $rightNode;
}
if ($this->contains(($upperNode = new AntiNode(new Coordinate($relay->row, $relay->column - $distance), [$originator->frequency]))->coordinate)) {
$this->antinodes[] = $upperNode;
}
}
continue;
}
/**
* The simple ones are accounted for. Now we must determine the location of nodes on a line
* with a given slope.
*/
$dx = fn ($slope) => ($distance / sqrt($distance+pow($slope,2)));
$dy = fn ($slope) => round(($slope * $dx($slope)),0);
echo "\tSlope: $slope\n\tDelta X: {$dx($slope)}\n\tDelta Y: {$dy($slope)}\n";
// We need to know which is "left"
if ($originator->column > $relay->column) {
// The relay is "left"
if ($this->contains(($node = new AntiNode(new Coordinate($relay->row - $dx($slope), $relay->column - $dy($slope)), ['.']))->coordinate)) {
$this->antinodes[] = $node;
}
if ($this->contains(($node = new AntiNode(new Coordinate($originator->row + $dx($slope), $originator->column + $dy($slope)), ['.']))->coordinate)) {
$this->antinodes[] = $node;
}
} else {
// The relay is to the right
if ($this->contains(($node = new AntiNode(new Coordinate($relay->row + $dy($slope), round($relay->column + $dx($slope))), ['1']))->coordinate)) {
$this->antinodes[] = $node;
echo "Added $node\nFrom $relay\n";
}
echo "DEBUG: $node\n";
// if ($this->contains(($node = new AntiNode(new Coordinate($originator->row - $dx($slope), $originator->column - $dy($slope)), ['2']))->coordinate)) {
// $this->antinodes[] = $node;
// }
}
}
}
Expand All @@ -233,6 +293,6 @@ private function findAntinodes(): self
echo $m.PHP_EOL;
echo $count = count($m->antinodes).PHP_EOL;

if (261 >= $count || $count >= 2455) {
if ((261 >= $count) || ($count >= 2455)) {
echo "WRONG!\n";
}

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