36 lines
1.4 KiB
PHP
36 lines
1.4 KiB
PHP
<?php
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echo '<pre>';
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$input = file('input', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
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$input = array_map(fn($line) => explode(',', str_replace(' -> ', ',', $line)), $input);
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$map = array_fill(0, 1000, array_fill(0, 1000, 0));
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foreach ($input as $coordinates) {
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if ($coordinates[0] === $coordinates[2]) {
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$start = min([$coordinates[1], $coordinates[3]]);
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$end = max([$coordinates[1], $coordinates[3]]);
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for ($i = $start; $i <= $end; $i++) {
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$map[$coordinates[0]][$i]++;
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}
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}
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if ($coordinates[1] === $coordinates[3]) {
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$start = min([$coordinates[0], $coordinates[2]]);
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$end = max([$coordinates[0], $coordinates[2]]);
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for ($i = $start; $i <= $end; $i++) {
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$map[$i][$coordinates[1]]++;
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}
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}
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if ($coordinates[0] !== $coordinates[2] && $coordinates[1] !== $coordinates[3]) {
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$startx = $start = min([$coordinates[0], $coordinates[2]]);
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$endx = max([$coordinates[0], $coordinates[2]]);
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$starty = $startx === $coordinates[0] ? $coordinates[1] : $coordinates[3];
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$endy = $startx === $coordinates[2] ? $coordinates[1] : $coordinates[3];
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$slope = $starty > $endy ? -1 : 1;
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for ($i = $startx, $step = 0; $i <= $endx; $i++, $step++) {
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$map[$i][$starty + ($step * $slope)]++;
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}
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}
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}
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echo count(array_filter(call_user_func_array('array_merge', $map), fn($el) => $el > 1)); //22213
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