剑指Offer38-数值的整数次方

考虑全面点就行。

# -*- coding:utf-8 -*-
class Solution:
    def Power(self, base, exponent):
        # write code here
        tmp = base
        if base == 0 and exponent < 0:  # 0……-1 ×
            return None
        if base == 0 and exponent > 0:  # 0……1 0
            return 0
        if exponent == 0:
            return 1
        
        if exponent < 0:  # 1……-2
            for i in range((-exponent)-1):
                base *= tmp
            return 1/base
        
        if exponent > 0:
            for i in range(exponent-1):
                base *= tmp
            return base