add

@@ -48,7 +48,11 @@ public class ExeProjectTask implements Runnable {
                 if (array.length <= 4) {
                     firstLength = 1;
                 } else {
-                    firstLength = array.length / 2 - 1;
+                    if ((array.length - 1) % 2 == 0){
+                        firstLength = (array.length - 1) / 2;
+                    }else {
+                        firstLength = (array.length - 1) / 2 - 1;
+                    }
                 }
 
                 for (int i = 0; i < array.length; i++) {