Return the integer square root of n: the largest integer r with r * r <= n.
n can have up to 200 digits.
Example 1
Input:
exact_isqrt(26)
Output:
5
5 * 5 = 25 <= 26 < 36.
Example 2
Input:
exact_isqrt(999999999999999999)
Output:
999999999
A float gives 1000000000.0, which is one too many.
0 <= n < 10**200No results yet
Run your code to check it against the examples, or submit to run every test.