The API: int read4(char* buf) reads 4 characters at a time from a file. The return value is the actual number of characters read. For example, it returns 3 if there is only 3 characters left in the file. By using the read4 API, implement the function int read(char* buf, int n) that reads n characters from the file. Note: The read function will only be called once for each test case.
O(n)
O(n)
Run make to build and run C++ files and run Swift files. Or you can run .playground file.