diff --git a/src/fast_cal/fast_cal.cc b/src/fast_cal/fast_cal.cc
index ecec5af..e981b7b 100644
--- a/src/fast_cal/fast_cal.cc
+++ b/src/fast_cal/fast_cal.cc
@@ -31,7 +31,7 @@ int FastCal::step_num(RawCode code) {
     return num;
 }
 
-std::vector<RawCode> FastCal::backtrack(RawCode code) {
+std::vector<RawCode> FastCal::backtrack(const RawCode &code) {
     auto tmp = cases.find((uint64_t)code);
     if (tmp == cases.end()) {
         return std::vector<RawCode>{}; // code not exist
@@ -50,7 +50,11 @@ std::vector<RawCode> FastCal::resolve(RawCode start) {
     return FastCal::search(start, resolved);
 }
 
-std::vector<RawCode> FastCal::search(RawCode start, const FastCal::match_t &match) {
+std::vector<std::vector<RawCode>> FastCal::resolve_multi(RawCode start) {
+    return FastCal::search_multi(start, resolved);
+}
+
+std::vector<RawCode> FastCal::search(RawCode start, const match_t &match) {
     auto fc = FastCal();
     auto result = fc.target(start, match);
     if (result == FC_NOT_FOUND) {
@@ -58,3 +62,12 @@ std::vector<RawCode> FastCal::search(RawCode start, const FastCal::match_t &matc
     }
     return fc.backtrack(result); // backtrack target path
 }
+
+std::vector<std::vector<RawCode>> FastCal::search_multi(RawCode start, const match_t &match) {
+    auto fc = FastCal();
+    std::vector<std::vector<RawCode>> result;
+    for (const auto &c : fc.target_multi(start, match)) {
+        result.emplace_back(fc.backtrack(c)); // backtrack every target
+    }
+    return result;
+}
diff --git a/src/fast_cal/fast_cal.h b/src/fast_cal/fast_cal.h
index d5af9c7..22e2b2d 100644
--- a/src/fast_cal/fast_cal.h
+++ b/src/fast_cal/fast_cal.h
@@ -17,7 +17,7 @@ public:
 
     /// backtrack functions
     int step_num(RawCode code);
-    std::vector<RawCode> backtrack(RawCode code);
+    std::vector<RawCode> backtrack(const RawCode &code);
 
     /// BFS search functions
     // TODO: build function with void return -> build total tree
@@ -28,13 +28,14 @@ public:
     std::vector<RawCode> target_multi(RawCode code, const match_t &match);
 
     /// static BFS search functions
+    // TODO: (RawCode code) -> (const RawCode &code)
 //    static std::vector<RawCode> get_furthest(RawCode start);
 
     static std::vector<RawCode> resolve(RawCode start);
     static std::vector<RawCode> search(RawCode start, const match_t &match);
 
-//    static std::vector<std::vector<RawCode>> resolve_multi(RawCode start);
-//    static std::vector<std::vector<RawCode>> search_multi(RawCode start, const match_t &match);
+    static std::vector<std::vector<RawCode>> resolve_multi(RawCode start);
+    static std::vector<std::vector<RawCode>> search_multi(RawCode start, const match_t &match);
 
 private:
     struct fast_cal_t {
diff --git a/src/main.cc b/src/main.cc
index 416f42a..8d03fc6 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -45,10 +45,16 @@ int main() {
 //        std::cout << "step number: " << f.step_num(ret) << std::endl;
 //    }
 
-    for (const auto &c : FastCal::resolve(RawCode::from_common_code("1a9bf0c"))) {
-        std::cout << c << std::endl;
-    }
+//    for (const auto &c : FastCal::resolve(RawCode::from_common_code("1a9bf0c"))) {
+//        std::cout << c << std::endl;
+//    }
 
+    for (const auto &s : FastCal::resolve_multi(RawCode::from_common_code("1a9bf0c"))) {
+//        for (const auto &c : s) {
+//            std::cout << c << std::endl;
+//        }
+//        std::cout << "--------------------------------------------" << std::endl;
+    }
 
 //    std::cout << f.step_num(ret) << std::endl;