Even though Python natively supports big integers, taking the nth root of very large numbers can fail in Python.
x = 2 ** 100
cube = x ** 3
root = cube ** (1.0 / 3)
OverflowError: long int too large to convert to float
When dealing with such large integers, you will need to use a custom function to compute the nth root of a number.
def nth_root(x, n):
# Start with some reasonable bounds around the nth root.
upper_bound = 1
while upper_bound ** n <= x:
upper_bound *= 2
lower_bound = upper_bound // 2
# Keep searching for a better result as long as the bounds make sense.
while lower_bound < upper_bound:
mid = (lower_bound + upper_bound) // 2
mid_nth = mid ** n
if lower_bound < mid and mid_nth < x:
lower_bound = mid
elif upper_bound > mid and mid_nth > x:
upper_bound = mid
else:
# Found perfect nth root.
return mid
return mid + 1
x = 2 ** 100
cube = x ** 3
root = nth_root(cube, 3)
x == root
# True