Binary Exponentiation or Pow(x,y)

'''
Binary Exponentiation:
eg x=2 , y=10
we can also write it as : x=4 ie. base*base 2*2 and exponent=y/2 ie. 5 ie. overall 4^5
we can also write it as : 4^5=4*(4^4)
we can also write it as : 4*(4^4)=4*(16^2)
we can also write it as : 4*256^1   {256 =16*16}

Algo:
Base and exponent
if exponent is divisible by 2 then multiply base with base eg base*base
if exponent is not divisible by 2 then multiply base in some variable eg. ans
for example ans=1,base=5 and exponent=3 so answer is 125 then  ans=1*5,base=5 and
exponent=2(ie. exponent-1) so answer is 1*5*(5^2) =125

if exponent>0 ans=x^exponent
if exponenet<0 ans=1/(x^exponent)
so we need to store absolute value of exponenet.
'''
class Solution:
    def myPow(self, x: float, n: int) -> float:
        if n==0:
            return 1
        ans=1
        sign=1
        base=x
        if n<0:
            sign=-1
            n=abs(n)
        while n>1:
            if n%2==0:
                base=base*base
                n//=2
            else:
                ans=ans*base
                n-=1
        return ans*base if sign==1 else 1/(ans*base)