Online PHP editor | refs for u2sAI

<?php $memoize = function ($fn, $cacheKeyFn = null, $limit = null) { $cache = array(); return function () use ($fn, $cacheKeyFn, $limit, & $cache) { $args = func_get_args(); if ($cacheKeyFn) { $key = call_user_func_array($cacheKeyFn, $args); } else { $key = reset($args); } if (isset($cache[$key])) { return $cache[$key]; } $result = call_user_func_array($fn, $args); if ($limit !== null && count($cache) === $limit) { array_shift($cache); } $cache[$key] = $result; return $result; }; }; $numCalls = 0; $memoFib = $memoize( function ($n) use (& $memoFib, & $numCalls) { $numCalls++; if ($n === 1 || $n === 2) return 1; return $memoFib($n - 1) + $memoFib($n - 2); } ); echo $numCalls . PHP_EOL; echo $memoFib(0) . PHP_EOL; echo $memoFib(1) . PHP_EOL;