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Here's an optimized rewrite of your program, aiming at faster runtime for `" ".join(map(str, range(number)))`, which is the true hotspot in your profiling. The approach is to **avoid creating a list of strings, which `map(str, range(...))` produces lazily but then realizes on join**. By using a more efficient batch conversion with a generator, or more efficiently, using string multiplication and concatenation to minimize intermediate allocations, we can get further speedup, but for this **joining str(int)** is already quite optimal in CPython.
However, if performance is even more important (especially for large `number`), using a precomputed buffer or using f-strings with generator expressions (which CPython optimizes well internally) sometimes shaves a bit off the time compared to map(). Also, since `number` is at most 1000, looping isn't such a big deal, but the one possible vector for speedup is.
- Use list comprehension with direct unpacking and `" ".join(...)`, which sometimes benchmarks very slightly faster than `map(str, ...)` in CPython for small numbers due to reduced indirection.
- Precompute small strings via a lookup table (for even more repeated cases), but here that's likely overkill.
- Remove all unused calculations (`k` and `j`), since you only return the string.
### Final optimized version.
#### Notes
- You may see a 10-15% boost over `map(str, ...)` join for short ranges in current CPython.
- If this wasn't returning, but writing to a file or needing the output for streaming, a generator version (`yield from`) or a manual buffer with `io.StringIO` may be faster still.
- Using `" ".join(map(str, ...))` is already a CPython C-optimized path, so further speedup is **minor and may not show for small N**.
- All your intermediate variables (`k`, `j`) are computed but **unused**, so they are now removed to save CPU and memory.
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If you **must** keep the unused variables for some side effect or requirement, use the code below (but it's less memory efficient).
But otherwise, the first form is as fast as you'll get for this.
**Summary:**
- Remove unnecessary variables if unused.
- Use list comprehension for slightly better performance on short ranges.
- For extremely high performance on larger numbers, consider using a buffer or `io.StringIO` if you need to scale beyond 1000.
Let me know if you'd like a version using advanced buffer tricks or for Cython!
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