LeetCode CMake

A CMake project template for LeetCode.

Features

• CMake project
• Local playground
• Unit test and benchmark
• Cross platform

File Structure

LeetCodeCMake
├── CMakeLists.txt           # Project wide setup
├── src
│   ├── CMakeLists.txt       # Target collection
│   ├── include
│   │   ├── CMakeLists.txt   # Library collection
│   │   ├── catch.h          # Catch2 header file
│   │   └── leetcode.h       # Leetcode header file
│   └── L0001                # Problem 1
│       ├── L0001.h          #   Solution file
│       ├── L0001.cpp        #   Playground main
│       └── TestL0001.cpp    #   Test main
├── cmake                    # CMake modules
│   ├── Catch.cmake          
│   └── CatchAddTests.cmake 
└── build                    # Build directory

Usage

To run the example project, you need a complier with C++17 support.

1. Clone & Build

Build and test the project in command line.

$ cmake -B build
$ cmake --build build --target TestL0001 L0001
$ cd build 

$ ctest -R L0001 # run tests in problem L0001
Test project D:/code/learn_cmake/build
    Start 1: L0001
1/1 Test #1: L0001 ............................   Passed    0.02 sec

100% tests passed, 0 tests failed out of 1

# run all tests and benchmark in problem L001
$ ./src/Debug/TestL0001 # Windows, multi-configure build
$ ./src/TestL0001 # Linux, single-configure build
-------------------------------------------------------------------------------
L0001_Benchmark
-------------------------------------------------------------------------------
/src/L0001/TestL0001.cpp(32)
...............................................................................

benchmark name                       samples       iterations    estimated
                                     mean          low mean      high mean
                                     std dev       low std dev   high std dev
-------------------------------------------------------------------------------
Brute Force                                    100             1    190.132 ms 
                                        706.525 us    585.886 us    874.196 us 
                                        718.779 us    563.925 us    971.882 us

Hash Map                                       100             1    20.7629 ms 
                                        187.329 us    170.959 us    206.033 us 
                                        88.9449 us    75.6476 us    107.436 us

Hash Map2                                      100             1    860.129 ms 
                                        9.20266 ms    9.10087 ms     9.3058 ms 
                                        523.041 us    467.378 us    615.805 us


===============================================================================
All tests passed (9 assertions in 2 test cases)

# run playground for problem L0001
$ ./src/Debug/L0001 # Windows, multi-configure build
$ ./src/L0001 # Linux, single-configure build
[2, 7, 11, 15] 
9
[0, 1]

You can also open this directory using VSCode with CMake Tools extension, or open this directory using VS2019+ to run the target more easily.

2. Add new problems

• Problem directory: src/LXXX
• Problem header: src/LXXX.h, include leetcode.h
• [Optional] Playground source: src/LXXX.cpp, include LXXX.h
• [Optional] Test source: src/TestLXXX.cpp, include LXXX.h and catch.h
• Rebuild

Read TestL0001.cpp and TestL0002.cpp to learn hwo to write basic catch test cases. Refer to catch tutorial and benchmark for more complicated usage.

Leetcode Header

Some widely used leetcode structs and functions are inlucded in src/include/leetcode.h

• ListNode/TreeNode
• trimLeftTrailingSpaces/trimRightTrailingSpaces
• stringToInteger/stringToString/boolToString
• stringToIntegerVector/integerVectorToString
• stringToListNode/listNodeToString
• stringToTreeNode

Used STL: iostream/sstream/cstdlib/cassert/string/vector/queue

Compromises

Some compromises for convenience but not best practices:

1. Use file(GLOB ...) to collect targets: CMake is not automatically re-run when removing or adding files. Even though the CONFIGURE_DEPENDS flag can fix it, there is still a cost to perform the check on every rebuild.

2. Use #define CATCH_CONFIG_MAIN in every test file, which will repeated compiling the catch.hpp for each test. However, we just want a runnable test for each problem, so we don't need a super test program. Avoid building all targets at once.

3. Implement all methods in LXXXX.hpp to keep the project simple.

Q&A

1. How to debug the playground with vscode?

   Install the vscode-cmake-tools extension and configure the launch.json according to https://vector-of-bool.github.io/docs/vscode-cmake-tools/debugging.html.
   This is an example for gdb. You can create a default template launch.json on your platform and make sure that program, externalConsole and enviroment are set correctly.

2. How to change the C++ standard?

   Change the line set(CMAKE_CXX_STANDARD 20) in the top level CMakeLists.txt.

Acknowledge

• CMake
• Catch2
• LeetCode