function sell($coin)
{
static $sellCache = [1 => 1, 0 => 0];
if (array_key_exists($coin, $sellCache)) {
return $sellCache[$coin];
}
return $sellCache[$coin] = max($coin, sellCoins(exchange($coin)));
}
function sortHeap(&$array, $heapsize)
{
while ($heapsize) {
exchange($array[0], $array[$heapsize - 1]);
$heapsize = $heapsize - 1;
build_heap($array, 0, $heapsize);
}
}
<?php
$sellCache = [1 => 1, 0 => 0];
function exchange($coin)
{
return [floor($coin / 2), floor($coin / 3), floor($coin / 4)];
}
$sell = function ($coin) use(&$sellCache, &$sell) {
if (array_key_exists($coin, $sellCache)) {
return $sellCache[$coin];
}
$exchangedCoinsValue = array_reduce(exchange($coin), function ($acc, $coin) use($sell) {
return $acc + $sell(intval($coin));
}, 0);
return $sellCache[$coin] = max($coin, $exchangedCoinsValue);
};
while ($line = fscanf(STDIN, "%d\n")) {
list($number) = $line;
echo $sell($number) . "\n";
}
