54 lines
1.5 KiB
PHP
54 lines
1.5 KiB
PHP
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<?php
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$grid = array_map('str_split', explode("\n", file_get_contents('./input.txt')));
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$flashes = 0;
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for ($i = 0; $i < 100; $i++) {
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foreach ($grid as $k => $row) {
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foreach ($row as $j => $cell) {
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$grid[$k][$j]++;
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}
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}
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while(has_more_than_nine($grid)) {
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foreach ($grid as $k => $row) {
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foreach ($row as $j => $cell) {
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if ($grid[$k][$j] > 9) {
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foreach (range(-1, 1) as $r) {
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foreach (range(-1, 1) as $c) {
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if ($r === 0 && $c === 0) {
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$grid[$k+$r][$j+$c] = 0;
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}
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if (
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array_key_exists($k+$r, $grid) &&
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array_key_exists($j+$c, $grid[$k+$r]) &&
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$grid[$k+$r][$j+$c] !== 0
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) {
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$grid[$k+$r][$j+$c]++;
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}
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}
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}
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$flashes++;
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}
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}
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}
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}
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echo sprintf('After step %u%s%s%s', $i + 1, "\n", implode("\n", array_map('implode', $grid)), "\n", "\n");
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}
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echo $flashes;
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function has_more_than_nine($grid)
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{
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foreach ($grid as $row) {
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foreach ($row as $cell) {
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if ($cell > 9) {
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return true;
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}
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}
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}
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return false;
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}
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