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<?php function roll ($probability, $precision = 5) { return mt_rand(1, pow(10, $precision) / $probability) / pow(10, $precision); } $rolls = array(); for ($i = 0; $i < 500; $i++) { $rolls[roll(0.25)]++; } var_dump($rolls);

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33.18 ms | 402 KiB | 5 Q