91 lines
1.7 KiB
PHP
91 lines
1.7 KiB
PHP
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<?php
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$instructions = explode("\n", file_get_contents('./input.txt'));
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$h = [0,0];
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$t = [0,0];
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$places = ["0-0"];
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$grid = [
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['#'],
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];
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foreach ($instructions as $instruction) {
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[$direction, $length] = explode(' ', $instruction);
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for ($i = 0; $i < $length; $i++) {
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$newH = $h;
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switch ($direction) {
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case 'U':
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$newH[0]++;
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break;
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case 'R':
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$newH[1]++;
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break;
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case 'D':
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$newH[0]--;
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break;
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case 'L':
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$newH[1]--;
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break;
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}
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if (areTooFarAway($newH, $t)) {
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$t = $h;
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$places[] = implode('-', $h);
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$grid[$h[0]][$h[1]] = '#';
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}
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$h = $newH;
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}
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}
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displayGrid($grid);
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echo count(array_unique($places));
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/**
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* @param int[] $x
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* @param int[] $y
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*
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* @return bool
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*/
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function areTooFarAway($x, $y): bool
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{
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for ($i = $x[0] - 1, $l = $x[0] + 1; $i <= $l; $i++) {
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for ($j = $x[1] - 1, $m = $x[1] + 1; $j <= $m; $j++) {
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if ($y[0] === $i && $y[1] === $j) {
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return false;
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}
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}
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}
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return true;
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}
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/**
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* @param array $grid
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*
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* @return void
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*/
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function displayGrid($grid): void
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{
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$maxRow = 0;
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foreach ($grid as $item) {
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$maxRow = max($maxRow, count($item));
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}
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$grid = array_reverse($grid);
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foreach ($grid as $iValue) {
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for ($j = 0; $j <= $maxRow; $j++) {
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if (isset($iValue[$j])) {
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echo $iValue[$j];
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} else {
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echo '.';
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}
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}
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echo "\n";
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}
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}
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