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Yes, variations of this problem are commonly asked in coding interviews at major tech companies. It tests a candidate’s understanding of API-based design, simulation, and careful handling of buffers and edge cases.
Only simple arrays or character buffers are needed for this problem. A small temporary array of size four stores characters returned by read4(), while the destination buffer holds the final result.
The optimal approach repeatedly calls the read4() API and copies characters into the destination buffer until n characters are collected or the file ends. A temporary buffer of size four is used to store each batch of characters. This ensures efficient simulation with minimal extra space.
The read4() API always reads up to four characters at a time, which may exceed the remaining characters needed. A temporary buffer allows you to safely store these characters and copy only the required amount into the final output buffer.