diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..42afabf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/build
\ No newline at end of file
diff --git a/2/day1.md b/2/day1.md
deleted file mode 100644
index e69de29..0000000
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..3439ab4
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 3.15)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+add_compile_options(-Wall)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE Debug)
+endif()
+
+message("Build type is [${CMAKE_BUILD_TYPE}]")
+
+
+project(alg2025)
+
+include_directories(${CMAKE_CURRENT_LIST_DIR}/src/include)
+
+file(GLOB_RECURSE SRC_LIST CONFIGURE_DEPENDS ${CMAKE_CURRENT_LIST_DIR}/src/*.cpp)
+
+foreach(SRC IN LISTS SRC_LIST)
+    get_filename_component(SRC_NAME_WE ${SRC} NAME_WE)
+    message("[${SRC}] will be build to [${SRC_NAME_WE}]")
+    add_executable(${SRC_NAME_WE} ${SRC})
+endforeach()
diff --git a/src/2/day1.md b/src/2/day1.md
new file mode 100644
index 0000000..284a0a5
--- /dev/null
+++ b/src/2/day1.md
@@ -0,0 +1 @@
+GCD CRT
\ No newline at end of file