44 lines
1.1 KiB
PHP
44 lines
1.1 KiB
PHP
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<?php
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$map = array_map('str_split', explode("\n", file_get_contents('./input.txt')));
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$numRows = count($map);
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$numCols = count($map[0]);
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$visibles = ($numRows - 2) * 2 + ($numCols * 2); // edges
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for ($i = 1; $i <= $numRows - 2; $i++) {
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for ($j = 1; $j <= $numCols - 2; $j++) {
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if (isVisible($i, $j, $map)) {
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$visibles++;
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echo sprintf('{%u, %u} {%u} is visible %s', $i, $j, $map[$i][$j], "\n");
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} else {
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echo sprintf('{%u, %u} {%u} is NOT visible %s', $i, $j, $map[$i][$j], "\n");
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}
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}
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}
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echo $visibles;
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/**
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* @param int $x
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* @param int $y
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* @param array $map
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*
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* @return bool
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*/
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function isVisible(int $x, int $y, array $map): bool
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{
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$currentNumber = (int)$map[$x][$y];
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$row = $map[$x];
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if (max(array_slice($row, 0, $y)) < $currentNumber || max(array_slice($row, $y + 1)) < $currentNumber) {
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return true;
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}
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array_unshift($map, null);
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$map = array_map(...$map);
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$col = $map[$y];
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return max(array_slice($col, 0, $x)) < $currentNumber || max(array_slice($col, $x + 1)) < $currentNumber;
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}
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