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<?php function isPerfect($n) { return count($n)==4&&$n[0]*$n[1]*$n[2]*$n[3]+1==pow(pow($n[0],2)+3*$n[0]+1,2); } var_dump(isPerfect([1,2,3,4])); var_dump(isPerfect(['1','2','3','4'])); var_dump(isPerfect([3,9,5,6])); var_dump(isPerfect([1,2,3,4,5])); var_dump(isPerfect(['a','b','c','d'])); var_dump(isPerfect([1,'b',3,4])); var_dump(isPerfect([1001,1002,1003,1004]));

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46.48 ms | 402 KiB | 5 Q