A quick post on two functions for PHP that provide factorial and combination support.
function factorial($n) {
if ($n <= 1) {
return 1;
} else {
return factorial($n - 1) * $n;
}
}
function combinations($n, $k) {
//note this defualts to 0 if $n < $k
if ($n < $k) {
return 0;
} else {
return factorial($n)/(factorial($k)*factorial(($n - $k)));
}
}
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