coding

My own coding practice

To do

• Binary search
• Self balancing binary search tree
• Remove repeated elements in array without sorting them
• Two-pointer problems

1. Data structures:

   • Arrays, Linked Lists, Stacks, Queues, Trees, Graphs, Heaps, Hash sets, Hash maps

2. Algorithms:

   • Breadth first search, Depth first search, Binary search,
   • Quicksort, Mergesort,
   • A*,
   • Dynamic programming, Recursion, Divide and conquer

Git SSH access rights

if you get the error

> git@github.com: Permission denied (publickey).
> fatal: Could not read from remote repository.

Perform these steps:

1. cat /etc/resolv.conf has nameserver 8.8.4.4

2. Check git config --local --list

3. Add SSH key of your profile to ssh agent, ssh-add /<dir>/github/id_rsa

4. Enter ssh -T git@github.com

   Hi <username>! You've successfully authenticated, but GitHub does not provide shell access.
   

Unit tests

Linux Setup

Googletest could be added as a submodule or as a Linux utility

Development package, as a part of Linux tools

Download it as a pre-built library Guide here on dev package. By installing libgtest-dev, two directories are created

/usr/src/gtest
/usr/src/googletest

    sudo apt install libgtest-dev build-essential cmake
    cd /usr/src/gtest
    sudo cmake CMakeLists.txt
        -- Configuring done
        -- Generating done
        -- Build files have been written to: /usr/src/googletest/googletest
    sudo make

By this step, Two libs are built and linked;

/usr/src/gtest/lib/libgtest.a
/usr/src/gtest/lib/libgtest_main.a

Copy or symlink these two to /usr/lib

    sudo ln -s /usr/src/gtest/lib/libgtest.a /usr/lib
    sudo ln -s /usr/src/gtest/lib/libgtest_main.a /usr/lib

Build tests

In src/ and test/, the CMakeLists.txt allow them to compile independently. cmake CMakeLists.txt make There will be executables generated with the name provided

To collectively build src and unit test executables, and keep the auto-generated files contained in one directory only

    mkdir build && cd build
    cmake -S ../ -B . # -Src dir is parent, -Build dir is current 
    make

Run tests

To run the tests, go into build directory

    ./build/src/main # Only source code executable
    ./build/test/unittest_run 
        [==========] Running 3 tests from 1 test suite.
        [----------] Global test environment set-up.
        [----------] 3 tests from MyTest
        [ RUN      ] MyTest.valid_answers
        [       OK ] MyTest.valid_answers (0 ms)
        [  PASSED  ] 2 tests

Submodule method

git submodule add https://github.com/google/googletest.git
git submodule update --init --recursive
mkdir build/ && cd build
cmake -S ../ -B . # -Src dir is parent, -Build dir is current 
sudo ldconfig -v | egrep 'gtest|gmock'

Draft

Another method is

    sudo apt install googletest
    cd /usr/src/googletest/
    sudo cmake .
    sudo cmake --build . --target install

Files will be located in /usr/local/lib/libgtest_main.a /usr/local/lib/libgtest.a