// $low and $high have to be integers function binarysearch( $array, $key, $low, $high ){ if( $low > $high ) // termination case { return -1; } $middle = intval( ( $low+$high )/2 ); // gets the middle of the array if ( $array[$middle] == $key ) // if the middle is our key { return $middle; } elseif ( $key { return binarysearch( $array, $key, $low, $middle-1 ); } return binarysearch( $array, $key, $middle+1, $high ); // our key might be in the right sub-array}
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php