README.md

Disable clang-format for sections

Special comments can be added around sections are hand-formatted and you do not want to be reformatted be clang-format.

Like this:

// clang-format off
std::vector<int> testcases[][2] = {
  {
    {1, 3} , {2}
  },
  {
    {1, 2}, {3, 4}
  },
  {
    {0, 0}, {0, 0}
  },
  {
    {}, {1}
  },
  {
    {2}, {}
  }
};
// clang-format on

Note that the single space after the // is important.