⚡️ Speed up function fibonacci by 155%

[codeflash-ai]

📄 155% (1.55x) speedup for fibonacci in code_to_optimize_ts/fibonacci.ts

⏱️ Runtime : 4.04 microseconds → 1.58 microsecondss (best of 250 runs)

📝 Explanation and details

The optimized code achieves a 155% speedup by replacing the exponential-time recursive algorithm with a linear-time iterative approach.

Key optimization:

• Eliminated exponential recursion: The original code has O(2^n) time complexity because each call spawns two more recursive calls, creating a binary tree of redundant calculations. For example, fibonacci(5) recalculates fibonacci(3) multiple times.
• Iterative dynamic programming: The optimized version uses O(n) time complexity by computing each Fibonacci number exactly once in a bottom-up manner, storing only the previous two values.

Why this is faster:

1. Reduced function calls: Line profiler shows 1200 hits on line 12 (the recursive call line) in the original vs only 19 hits in the optimized version - a 98% reduction in function invocations
2. No redundant computation: Each Fibonacci number is calculated once instead of being recomputed exponentially many times
3. Eliminated call stack overhead: Iterative loops are much cheaper than recursive function calls in terms of memory allocation and stack management

Impact:
The speedup grows dramatically with larger inputs. For small values of n (like n≤10), the 155% improvement is already significant. For larger values (n=20-40), the difference would be orders of magnitude larger - potentially reducing runtime from seconds to microseconds.

This optimization is particularly valuable if the function is called frequently or with moderately large values of n in production workloads.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	✅ 22 Passed
🌀 Generated Regression Tests	🔘 None Found
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

⚙️ Click to see Existing Unit Tests

To edit these changes git checkout codeflash/optimize-fibonacci-mklqbw4t and push.