Nth root of given integer

[luckymastermin]

Hi All I need your help.

Can some one tell me how to find the nth root in fastest way. I am using binary search which O(log n) but is there any technique in python to get this done in O(1).

I tried with decimal and round function but for large inputs they are not giving correct answer all time.

any hint in python will be appreciated .

[leppyr64]

There is some useful information here:
en.m.wikipedia.org/wiki/Root-finding_algorithm

[min_25]

You can learn many basic algorithms (perhaps used in many BigInteger libraries) for integers here:
gmplib.org/manual/