Question

How to create a 2-letter permutation from A, B, C, and D in PHP

Answer 1

$letters = ['A', 'B', 'C', 'D'];
$n = count($letters);

echo "2-letter permutations:\n";

for ($i = 0; $i < $n; $i++) {
    for ($j = 0; $j < $n; $j++) {
        if ($i !== $j) {
            echo $letters[$i] . $letters[$j] . "\n";
        }
    }
}



/*
run:

2-letter permutations:
AB
AC
AD
BA
BC
BD
CA
CB
CD
DA
DB
DC

*/

 

70+ SQL courses for beginners and professionals