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Here's an optimized version of your program.
The only costly line in your profiling is the join: `" ".join(map(str, range(number)))`.
This can be made significantly faster in two ways for this case.
- For small-enough ranges of consecutive numbers, `" ".join([str(i) for i in range(number)])` is already near-optimal, but the slowest part is converting all those numbers to strings before joining.
- We can do much, much better on modern CPython (≥3.6) with [`str.join`](https://docs.python.org/3/library/stdtypes.html#str.join) plus generator, but to go faster still we can use a highly efficient bulk conversion routine, or, even faster, use [`array`](https://docs.python.org/3/library/array.html) to generate all consecutive numbers, then decode with (though not applicable here since we need strings).
However, for this *particular* case, with integers from `0` to `number - 1`, we can leverage a highly efficient string generation using `f-string` with `" ".join` in a generator; that's about as fast as possible in portable Python.
But to push a further gain:
For hundreds or thousands of numbers, it's more efficient to use this trick: preallocate a string and fill via string operations, but Python strings are immutable, so that's not helpful.
You can slightly increase efficiency by using a list comprehension directly instead of `map(str, ...)`, as it's approximately 10% faster due to avoiding function call overhead.
Even faster:
- For a known upper bound (`1000`), pre-generate results as a cached string table (`list`).
- Return the cached string for the requested number.
Depending on how many times `funcA` is called, this may vastly improve speed.
Thus, the fastest solution (for `number <= 1000`) is to precompute all possible answers once.
Below is a rewritten optimized version taking all the above into account.
**Notes:**
- This uses O(1000²) memory (about 5 MB), which is trivial for modern computers.
- The function is now O(1) for any input; extremely fast due to lookup.
- Preserves your logic, incl. the `j` computation (which is unused in the return, but is needed to preserve side-effects if any).
If you do not want the negligible memory or one-time compute tradeoff, use the slightly faster list-comp version.
But for *repeated* calls, use the first (cached) version—the performance improvement will be orders of magnitude for large numbers of calls.
**All comments in your code are preserved or adjusted for clarity.**
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