diff --git a/src/analyse/analyse.cc b/src/analyse/analyse.cc
index 46e4969..2dbbb68 100644
--- a/src/analyse/analyse.cc
+++ b/src/analyse/analyse.cc
@@ -8,6 +8,29 @@ void Analyse::set_root(const RawCode &code) {
     this->root = (uint64_t)code;
 }
 
+std::vector<RawCode> Analyse::layer_export(uint32_t layer_num) {
+    std::vector<RawCode> layer_cases;
+    for (const auto &tmp : cases) { // traverse every cases
+        if (tmp.second.step == layer_num) {
+            layer_cases.emplace_back(RawCode::unsafe_create(tmp.first));
+        }
+    }
+    return layer_cases;
+}
+
+std::vector<std::vector<RawCode>> Analyse::layer_export() {
+    std::vector<std::vector<RawCode>> layer_cases;
+    for (const auto &tmp : cases) { // traverse every cases
+        if (tmp.second.step >= layer_cases.size()) {
+            layer_cases.resize(tmp.second.step + 1);
+        }
+        layer_cases[tmp.second.step].emplace_back(
+            RawCode::unsafe_create(tmp.first) // insert at target layer
+        );
+    }
+    return layer_cases;
+}
+
 /// memory initialize and return klotski core
 Core Analyse::init(uint64_t code) {
     /// reset working data
diff --git a/src/analyse/analyse.h b/src/analyse/analyse.h
index 474ad52..883e1c0 100644
--- a/src/analyse/analyse.h
+++ b/src/analyse/analyse.h
@@ -22,6 +22,10 @@ public:
     void build();
     std::vector<RawCode> build_until(const match_t &match);
 
+    /// analysed layer export
+    std::vector<std::vector<RawCode>> layer_export();
+    std::vector<RawCode> layer_export(uint32_t layer_num);
+
 private:
     struct analyse_t {
         uint64_t code;
diff --git a/src/main.cc b/src/main.cc
index d061092..24f97ad 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -41,7 +41,7 @@ int main() {
 //    sleep(3);
 
 //    std::cout << "start benchmark" << std::endl;
-    auto start_time = clock();
+//    auto start_time = clock();
 
 
 //    {
@@ -54,21 +54,19 @@ int main() {
 
 
     auto a = Analyse(RawCode::from_common_code("1a9bf0c"));
-//    a.build();
-    auto ret = a.build_until([](uint64_t code) {
-        return ((code >> (3 * 0xD)) & 0b111) == B_2x2;
-    });
-    for (const auto &r : ret) {
-        std::cout << r << std::endl;
-    }
-
-//    auto ret = a.build_until((uint64_t)RawCode::from_common_code("1a9bf0c"), [](uint64_t code) {
+    a.build();
+//    auto ret = a.build_until([](uint64_t code) {
 //        return ((code >> (3 * 0xD)) & 0b111) == B_2x2;
 //    });
 //    for (const auto &r : ret) {
-//        std::cout << RawCode(r) << std::endl;
+//        std::cout << r << std::endl;
 //    }
 
+    auto start_time = clock();
+
+    std::cout << a.layer_export(81).size() << std::endl;
+    std::cout << a.layer_export()[81].size() << std::endl;
+
 //    auto raw_code = CommonCode("A5D3AF0").to_raw_code().unwrap();
 
 //    auto a = Analyse();