Perf optimize MemoryEfficientLongestCommonSubsequenceCalculator

Author: staabm

src/MemoryEfficientLongestCommonSubsequenceCalculator.php

@@ -78,7 +78,12 @@ private function length(array $from, array $to): array
                 if ($from[$i] === $to[$j]) {
                     $current[$j + 1] = $prev[$j] + 1;
                 } else {
-                    $current[$j + 1] = max($current[$j], $prev[$j + 1]);
+                    // don't use max() to avoid function call overhead
+                    if ($current[$j] > $prev[$j + 1]) {
+                        $current[$j + 1] = $current[$j];
+                    } else {
+                        $current[$j + 1] = $prev[$j + 1];
+                    }
                 }
             }
         }