diff --git a/all_cases/CMakeLists.txt b/all_cases/CMakeLists.txt
deleted file mode 100644
index a8d7f70..0000000
--- a/all_cases/CMakeLists.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-cmake_minimum_required(VERSION 3.0)
-set(CMAKE_CXX_STANDARD 14)
-
-add_executable(klotski short_code.cc)
diff --git a/all_cases/short_code.cc b/all_cases/short_code.cc
deleted file mode 100644
index 2d779c8..0000000
--- a/all_cases/short_code.cc
+++ /dev/null
@@ -1,55 +0,0 @@
-#include <iostream>
-#include <algorithm>
-#include "short_code.h"
-
-// TODO: try to remove: `0` `O` `I` `l`
-
-const uint32_t ALL_CASES_NUMBER = 29334498;
-
-std::string code_to_string(uint32_t short_code) {
-    if (short_code >= ALL_CASES_NUMBER) {
-        throw std::range_error("short code out of range");
-    }
-    std::string result(5, '\0'); // short code length 5
-    for (int i = 0; i < 5; ++i) {
-        uint8_t bit = short_code % 36;
-        short_code = (short_code - bit) / 36;
-        if (bit < 10) {
-            result[4 - i] = char(bit + 48); // 0 ~ 9
-        } else {
-            result[4 - i] = char(bit + 55); // A ~ Z
-        }
-    }
-    return result;
-}
-
-uint32_t code_from_string(const std::string &short_code) {
-    if (short_code.length() != 5) {
-        throw std::runtime_error("invalid short code");
-    }
-    uint32_t result = 0;
-    for (auto &bit : short_code) {
-        result *= 36;
-        if (bit >= '0' && bit <= '9') {
-            result += bit - 48; // 0 ~ 9
-        } else if (bit >= 'A' && bit <= 'Z') {
-            result += bit - 55; // A ~ Z
-        } else if (bit >= 'a' && bit <= 'z') {
-            result += bit - 87; // a ~ z
-        } else {
-            throw std::runtime_error("invalid short code");
-        }
-    }
-    if (result >= ALL_CASES_NUMBER) {
-        throw std::range_error("short code out of range");
-    }
-    return result;
-}
-
-int main() {
-
-//    std::cout << code_to_string(14323231) << std::endl;
-//    std::cout << code_from_string("8IzVj") << std::endl;
-
-    return 0;
-}
diff --git a/all_cases/short_code.h b/all_cases/short_code.h
deleted file mode 100644
index 2e8e473..0000000
--- a/all_cases/short_code.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#pragma once
-
-#include <cstdint>
-
-class ShortCode {
-public:
-    uint32_t zip_short_code(uint64_t code);
-    uint64_t unzip_short_code(uint32_t short_code);
-
-};