Python/divide_and_conquer/power.py

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def actual_power(a: int, b: int):
"""
Function using divide and conquer to calculate a^b.
It only works for integer a,b.
"""
if b == 0:
return 1
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))
def power(a: int, b: int) -> float:
"""
>>> power(4,6)
4096
>>> power(2,3)
8
>>> power(-2,3)
-8
>>> power(2,-3)
0.125
>>> power(-2,-3)
-0.125
"""
if b < 0:
return 1 / actual_power(a, b)
return actual_power(a, b)
if __name__ == "__main__":
print(power(-2, -3))