Whether given number is a power of any other natural number php?

Question

I tried to find For a given positive integer Z, check if Z can be written as P^Q, where P and Q are positive integers greater than 1. If Z can be written as P^Q, return 1, else return 0

I tried lots with online solution,

Check if one integer is an integer power of another

Finding if a number is a power of 2

but it's not what i need , any hint or any tips?

Answer 1

Here's the naive method - try every combination:

function check($z) {
    for($p = 2; $p < sqrt($z); $p++) {

        if($z % $p > 0) {
            continue;
        }

        $q = $p;

        for($i = 1; $q < $z; $i++) {
            $q *= $p;
        }

        if($q == $z) {
            //print "$z = $p^$i";
            return 1;
        }
    }

    return 0;
}

Similarly, using php's built in log function. But it may not be as accurate (if there are rounding errors, false positives may occur).

function check($z) {
    for($p = 2; $p < sqrt($z); $p++) {
        $q = log($z,$p);
        if($q == round($q)) {
            return 1;
        } 
    }

    return 0;
}