diff --git a/klotski/main.cc b/klotski/main.cc
index a9a2c8d..511a124 100644
--- a/klotski/main.cc
+++ b/klotski/main.cc
@@ -17,17 +17,19 @@ int main() {
 //        std::cout << temp.size() << std::endl;
 //    }
 
-    auto s = ShortCode();
+//    auto s = ShortCode();
+//    auto s = ShortCode(ShortCode::Mode::NORMAL);
+    auto s = ShortCode(ShortCode::Mode::FAST);
 
 //    s.speed_up(ShortCode::Mode::FAST);
-//    std::cout << s.all_cases_list.size() << std::endl;
-//    std::cout << s.all_cases_dict.size() << std::endl;
+    std::cout << s.all_cases_list.size() << std::endl;
+    std::cout << s.all_cases_dict.size() << std::endl;
 
 //    printf("%d\n", s.fast_encode(0x6EC0F8800));
 //    printf("%09lX\n", s.fast_decode(14323231));
 
-    s.speed_up(ShortCode::Mode::NORMAL);
-    std::cout << s.basic_ranges.size() << std::endl;
+//    s.speed_up(ShortCode::Mode::NORMAL);
+//    std::cout << s.basic_ranges.size() << std::endl;
 
     return 0;
 }
diff --git a/klotski/short_code.cc b/klotski/short_code.cc
index 6e93d61..ecf1342 100644
--- a/klotski/short_code.cc
+++ b/klotski/short_code.cc
@@ -44,3 +44,7 @@ uint32_t ShortCode::fast_encode(uint64_t common_code) { // common_code -> short_
     // TODO: ensure input common_code valid
     return all_cases_dict[common_code];
 }
+
+ShortCode::ShortCode(ShortCode::Mode mode) {
+    speed_up(mode);
+}
diff --git a/klotski/short_code.h b/klotski/short_code.h
index a6d0cf4..a253873 100644
--- a/klotski/short_code.h
+++ b/klotski/short_code.h
@@ -14,6 +14,9 @@ public:
     std::vector<uint64_t> all_cases_list;                  // short_code -> common_code
     std::unordered_map<uint64_t, uint32_t> all_cases_dict; // common_code -> short_code
 
+    ShortCode() = default;
+    explicit ShortCode(enum Mode mode);
+
     void speed_up(enum Mode mode);
 
 //    uint32_t zip_short_code(uint64_t code);