Optimize gcd_recursive

The optimization replaces recursion with iteration to eliminate function call overhead. The original recursive implementation makes ~27,165 recursive function calls (as shown in the line profiler), each requiring stack frame creation, parameter passing, and return value handling. The iterative version uses a simple `while` loop with tuple assignment to achieve the same mathematical result.

**Key changes:**
- Replaced recursive calls with `while b:` loop
- Used tuple assignment `a, b = b, a % b` for the Euclidean algorithm steps
- Eliminated ~27k function call overhead operations

**Why it's faster:**
- Function calls in Python are expensive due to stack frame management and parameter validation
- The iterative approach reduces the profiled execution time from 13.76ms to 4.69ms (65% reduction)
- Loop operations are much faster than recursive calls in Python's interpreter

**Performance characteristics:**
The optimization shows consistent 10-60% speedups across test cases, with the largest gains on cases requiring more iterations (like large coprime numbers showing 50-60% improvement). Simple cases with immediate termination (like `gcd(5, 0)`) show minimal improvement since they avoid most recursive overhead anyway. The optimization is particularly effective for the large-scale tests, showing 23-66% improvements on bulk operations.

Author: codeflash-ai[bot]

src/math/computation.py

@@ -1,5 +1,6 @@
 def gcd_recursive(a: int, b: int) -> int:
     """Calculate greatest common divisor using Euclidean algorithm with recursion."""
-    if b == 0:
-        return a
-    return gcd_recursive(b, a % b)
+    # Use an iterative approach to eliminate recursive call overhead
+    while b:
+        a, b = b, a % b
+    return a