function q44()
{
$pentagonalNumbers = [];
$i = 0;
while (true) {
$pentagonalNumber = Number::pentagonal(++$i);
$pentagonalNumbers[$pentagonalNumber] = $pentagonalNumber;
foreach ($pentagonalNumbers as $firstPentagonalNumber) {
$secondPentagonalNumber = $pentagonalNumber - $firstPentagonalNumber;
if ($firstPentagonalNumber === $secondPentagonalNumber) {
continue;
}
if (!isset($pentagonalNumbers[$secondPentagonalNumber])) {
continue;
}
$difference = $secondPentagonalNumber - $firstPentagonalNumber;
if (isset($pentagonalNumbers[$difference])) {
return $secondPentagonalNumber - $firstPentagonalNumber;
}
}
}
}
function q45($t, $p, $h)
{
$px = Number::pentagonal($p);
$tx = Number::triangle($t);
while (true) {
$hx = Number::hexagonal(++$h);
$count = 1;
while ($hx >= Number::pentagonal($p + 1)) {
$px = Number::pentagonal(++$p);
}
if ($px === $hx) {
++$count;
}
while ($hx >= Number::triangle($t + 1)) {
$tx = Number::triangle(++$t);
}
if ($tx === $hx) {
++$count;
}
if ($count === 3) {
return $hx;
}
}
}