Fix And Add power.py

To fix the inaccuracies and allow handling of negative exponents and bases, the key issue lies in how negative numbers are handled in the power calculation, especially when dividing.
## Example Output:
```python
>>> power(4, 6)
4096
>>> power(2, 3)
8
>>> power(-2, 3)
-8
>>> power(2, -3)
0.125
>>> power(-2, -3)
-0.125
```

Author: lighting9999

divide_and_conquer/power.py

@@ -19,12 +19,15 @@ def actual_power(a: int, b: int):
     """
     if b == 0:
         return 1
+    half = actual_power(a, b // 2)
+
     if (b % 2) == 0:
         return actual_power(a, int(b / 2)) * actual_power(a, int(b / 2))
     else:
-        return a * actual_power(a, int(b / 2)) * actual_power(a, int(b / 2))
-
-
+        return half * half
+    else:
+        return a * half * half
+        
 def power(a: int, b: int) -> float:
     """
     :param a: The base (integer).