Question

How to check if a number is composed of a pair of duplicate digits next to each other in PHP

Answer 1

function has_duplicate_pair_digits($n) {
    $digits = str_split($n);
    
    $total_digits = count($digits); 
    
    if ($total_digits % 2 == 1) { // total digits not even
        return false;
    }
    
    for ($i = 0; $i < $total_digits - 1; $i += 2) {
        echo $digits[$i] . " - " . $digits[$i + 1] . "\n";
        if ($digits[$i] != $digits[$i + 1]) {
            return false;
        }
    }
    
    return true;
}

$n = 33558877;

echo has_duplicate_pair_digits($n) ? "true" : "false";




/*
run:

3 - 3
5 - 5
8 - 8
7 - 7
true

*/

 

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