Did you implement void wave_sort(int arr[], int arr_size) or void wave_sort(const std::vectro<int> &v)? The tests have been rewritten a month ago to use the latter.

I have same question

Tbh, you don't really do that.

main.cpp:46:3: error: no matching function for call to 'wave_sort'
  wave_sort(v);
  ^~~~~~~~~
main.cpp:9:6: note: candidate function not viable: requires 2 arguments, but 1 was provided
void wave_sort (int arr[], int arr_size)

What is that mean?