Pow(x, n).py

# Implement pow(x, n), which calculates x raised to the power n (i.e., xn).

 

# Example 1:

# Input: x = 2.00000, n = 10
# Output: 1024.00000
# Example 2:

# Input: x = 2.10000, n = 3
# Output: 9.26100
# Example 3:

# Input: x = 2.00000, n = -2
# Output: 0.25000
# Explanation: 2-2 = 1/22 = 1/4 = 0.25
 

# Constraints:

# -100.0 < x < 100.0
# -231 <= n <= 231-1
# n is an integer.
# -104 <= xn <= 104


# solution
class Solution:
    def myPow(self, x: float, n: int) -> float:
        # po = x**n
         
        # print(format(po, '.5f'))
        m = abs(n)
        ans = 1.0
        while m:
            if m & 1:
                ans *= x
            x *= x
            m >>= 1
        return ans if n >= 0 else 1 / ans