diff --git a/klotski/main.cc b/klotski/main.cc
index 911e9c2..42aa8c0 100644
--- a/klotski/main.cc
+++ b/klotski/main.cc
@@ -30,36 +30,39 @@ int main() {
 //    printf("%09lX\n", s.unzip_short_code(14323231));
 
 
-    std::cout << "preparing..." << std::endl;
-    std::vector<uint64_t> all_cases;
-    auto a = AllCases(AllCases::ALL_CASES);
-    for (int head = 0; head < 16; ++head) {
-        uint64_t prefix = (uint64_t)head << 32;
-        for (const auto &range : (*a.get_all_cases())[head]) {
-            all_cases.emplace_back(prefix | range);
-        }
-    }
-
-//    auto s = ShortCode(ShortCode::Mode::NORMAL);
-    auto s = ShortCode(ShortCode::Mode::FAST);
-    std::cout << "start working" << std::endl;
-
-    for (auto short_code = 0; short_code < all_cases.size(); ++short_code) {
-        uint64_t common_code = all_cases[short_code];
+//    std::cout << "preparing..." << std::endl;
+//    std::vector<uint64_t> all_cases;
+//    auto a = AllCases(AllCases::ALL_CASES);
+//    for (int head = 0; head < 16; ++head) {
+//        uint64_t prefix = (uint64_t)head << 32;
+//        for (const auto &range : (*a.get_all_cases())[head]) {
+//            all_cases.emplace_back(prefix | range);
+//        }
+//    }
+//
+////    auto s = ShortCode(ShortCode::Mode::NORMAL);
+//    auto s = ShortCode(ShortCode::Mode::FAST);
+//    std::cout << "start working" << std::endl;
+//
+//    for (auto short_code = 0; short_code < all_cases.size(); ++short_code) {
+//        uint64_t common_code = all_cases[short_code];
+//
+//        if (short_code != s.zip_short_code(common_code)) {
+//            printf("ERROR: zip %d\n", short_code);
+//        }
+//        if (common_code != s.unzip_short_code(short_code)) {
+//            printf("ERROR: unzip %09lX\n", common_code);
+//        }
+//
+//        if (short_code % 2000000 == 0) {
+////        if (short_code % 10000 == 0) {
+//            std::cout << ((float)short_code / (float)all_cases.size() * 100) << "%" << std::endl;
+//        }
+//    }
+//    std::cout << "complete verify" << std::endl;
 
-        if (short_code != s.zip_short_code(common_code)) {
-            printf("ERROR: zip %d\n", short_code);
-        }
-        if (common_code != s.unzip_short_code(short_code)) {
-            printf("ERROR: unzip %09lX\n", common_code);
-        }
 
-        if (short_code % 2000000 == 0) {
-//        if (short_code % 10000 == 0) {
-            std::cout << ((float)short_code / (float)all_cases.size() * 100) << "%" << std::endl;
-        }
-    }
-    std::cout << "complete verify" << std::endl;
+    std::cout << ShortCode::code_to_string(14323231) << std::endl;
 
     return 0;
 }
diff --git a/klotski/short_code.cc b/klotski/short_code.cc
index b00b661..a4e61dc 100644
--- a/klotski/short_code.cc
+++ b/klotski/short_code.cc
@@ -13,6 +13,19 @@ bool ShortCode::check(uint32_t short_code) {
     return short_code < ShortCode::SHORT_CODE_LIMIT; // 0 ~ (SHORT_CODE_LIMIT - 1)
 }
 
+std::string ShortCode::code_to_string(uint32_t short_code) {
+    if (!ShortCode::check(short_code)) {
+        throw std::range_error("short code out of range");
+    }
+    std::string result(5, '\0'); // short code length 5
+    for (int n = 0; n < 5; ++n) {
+        uint8_t bit = short_code % 32;
+        short_code = (short_code - bit) / 32;
+        result[4 - n] = SHORT_CODE_TABLE[bit];
+    }
+    return result;
+}
+
 void ShortCode::speed_up(enum Mode mode) { // speed up handle short code
     switch (mode) {
         case Mode::NORMAL: // speed up into normal mode
diff --git a/klotski/short_code.h b/klotski/short_code.h
index d91c3da..d5715fa 100644
--- a/klotski/short_code.h
+++ b/klotski/short_code.h
@@ -1,9 +1,31 @@
 #pragma once
 
 #include <vector>
+#include <string>
 #include <cstdint>
 #include <unordered_map>
 
+const char SHORT_CODE_TABLE[32] = {
+    '1', '2', '3', '4', '5', '6', '7', '8', '9',
+    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'M',
+    'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
+};
+
+// 1 -> 48
+// ...
+// 9 -> 57
+// A -> 65
+// ...
+// H -> 72
+// J -> 74
+// ...
+// K -> 75
+// M -> 77
+// N -> 78
+// P -> 80
+// ...
+// Z -> 90
+
 class ShortCode {
 public:
     enum Mode {NORMAL, FAST};
@@ -12,9 +34,13 @@ public:
     void speed_up(enum Mode mode);
     explicit ShortCode(enum Mode mode);
     static bool check(uint32_t short_code);
+
     uint32_t zip_short_code(uint64_t common_code);
     uint64_t unzip_short_code(uint32_t short_code);
 
+    static std::string code_to_string(uint32_t short_code);
+//    static uint32_t code_from_string(const std::string &short_code);
+
 private:
     static const uint32_t SHORT_CODE_LIMIT = 29334498;