diff --git a/.gitmodules b/.gitmodules
index 390c373c..02434720 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,6 @@
 [submodule "includes/testlib"]
 	path = includes/testlib
 	url = https://github.com/MikeMirzayanov/testlib.git
+[submodule "includes/ac-library"]
+	path = includes/ac-library
+	url = https://github.com/atcoder/ac-library.git
diff --git a/.vscode/c_cpp_properties.json b/.vscode/c_cpp_properties.json
index 1d46630b..beec67a1 100644
--- a/.vscode/c_cpp_properties.json
+++ b/.vscode/c_cpp_properties.json
@@ -42,7 +42,8 @@
         {
             "name": "Linux",
             "includePath": [
-                "${workspaceFolder}/**"
+                "${workspaceFolder}/includes/testlib/**",
+                "${workspaceFolder}/includes/ac-library/**"
             ],
             "defines": [
                 "_DEBUG",
diff --git a/.vscode/settings.json b/.vscode/settings.json
index 4e20d03d..ff81fd94 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,95 +1,11 @@
 {
-    "files.associations": {
-        "iostream": "cpp",
-        "chrono": "cpp",
-        "random": "cpp",
-        "limits": "cpp",
-        "valarray": "cpp",
-        "cmath": "cpp",
-        "array": "cpp",
-        "atomic": "cpp",
-        "*.tcc": "cpp",
-        "bitset": "cpp",
-        "cctype": "cpp",
-        "cfenv": "cpp",
-        "charconv": "cpp",
-        "cinttypes": "cpp",
-        "clocale": "cpp",
-        "codecvt": "cpp",
-        "complex": "cpp",
-        "condition_variable": "cpp",
-        "csetjmp": "cpp",
-        "csignal": "cpp",
-        "cstdarg": "cpp",
-        "cstddef": "cpp",
-        "cstdint": "cpp",
-        "cstdio": "cpp",
-        "cstdlib": "cpp",
-        "cstring": "cpp",
-        "ctime": "cpp",
-        "cuchar": "cpp",
-        "cwchar": "cpp",
-        "cwctype": "cpp",
-        "deque": "cpp",
-        "forward_list": "cpp",
-        "list": "cpp",
-        "unordered_map": "cpp",
-        "unordered_set": "cpp",
-        "vector": "cpp",
-        "exception": "cpp",
-        "algorithm": "cpp",
-        "functional": "cpp",
-        "iterator": "cpp",
-        "map": "cpp",
-        "memory": "cpp",
-        "memory_resource": "cpp",
-        "numeric": "cpp",
-        "optional": "cpp",
-        "ratio": "cpp",
-        "regex": "cpp",
-        "set": "cpp",
-        "string": "cpp",
-        "string_view": "cpp",
-        "system_error": "cpp",
-        "tuple": "cpp",
-        "type_traits": "cpp",
-        "utility": "cpp",
-        "fstream": "cpp",
-        "future": "cpp",
-        "initializer_list": "cpp",
-        "iomanip": "cpp",
-        "iosfwd": "cpp",
-        "istream": "cpp",
-        "mutex": "cpp",
-        "new": "cpp",
-        "ostream": "cpp",
-        "scoped_allocator": "cpp",
-        "shared_mutex": "cpp",
-        "sstream": "cpp",
-        "stdexcept": "cpp",
-        "streambuf": "cpp",
-        "thread": "cpp",
-        "typeindex": "cpp",
-        "typeinfo": "cpp",
-        "any": "cpp",
-        "bit": "cpp",
-        "variant": "cpp",
-        "rope": "cpp",
-        "compare": "cpp",
-        "concepts": "cpp",
-        "coroutine": "cpp",
-        "numbers": "cpp",
-        "ranges": "cpp",
-        "span": "cpp",
-        "stop_token": "cpp"
-    },
     "go.formatTool": "goformat",
     "go.formatFlags": ["-style", "indent=4"],
     "code-runner.fileDirectoryAsCwd": true,
     "code-runner.runInTerminal": true,
     "code-runner.executorMap": {
         "c": "gcc $fileName -o $fileNameWithoutExt.exe -O2 -lm && ./$fileNameWithoutExt.exe",
-        "cpp": "g++ --std=c++14 $fileName -o $fileNameWithoutExt.exe -O2 -lm -fsanitize=address,undefined -fno-ms-extensions -Wall && ./$fileNameWithoutExt.exe",
+        "cpp": "g++ --std=c++14 $fileName -o $fileNameWithoutExt.exe -O2 -lm -I \"$(git rev-parse --show-toplevel)/includes/testlib\" -I \"$(git rev-parse --show-toplevel)/includes/ac-library\" -fsanitize=address,undefined -fno-ms-extensions -Wall && ./$fileNameWithoutExt.exe",
         "python": "python -u $fileName",
         "go": "go run $fileName",
         "javascript": "node $fileName",
diff --git a/includes/ac-library b/includes/ac-library
new file mode 160000
index 00000000..f669803f
--- /dev/null
+++ b/includes/ac-library
@@ -0,0 +1 @@
+Subproject commit f669803f78c3acc72671ca6e41b4eeb0469364a8