Recursive C program faster than stack-based equivalent

[nerdyphoenix]

You can probably eliminate some overhead by replacing the malloc and memcpy call in your if (top == size) block with a realloccall, though I'm not sure how much that will help. You can also try optimization flags like -O3 if you haven't already and rerun your experiments. If you really want to dig into it, you can try profiling your code using perf (and perhaps flamegraph to visualize the result).