import pyutil as pyu
pyu.get_local_pyinfo()

print(pyu.ps2("python-dotenv"))

from typing import List

class Solution:
  def findDuplicate(self, nums: List[int]) -> int:
    slow = nums[nums[0]]
    fast = nums[nums[nums[0]]]

    while slow != fast:
      slow = nums[slow]
      fast = nums[nums[fast]]

    slow = nums[0]

    while slow != fast:
      slow = nums[slow]
      fast = nums[fast]

    return slow

new Solution().findDuplicate()