### https://theweeklychallenge.org/blog/perl-weekly-challenge-300/
"""

Task 2: Nested Array

Submitted by: [55]Mohammad Sajid Anwar
     __________________________________________________________________

   You are given an array of integers, @ints of length n containing
   permutation of the numbers in the range [0, n - 1].

   Write a script to build a set, set[i] = ints[i], ints[ints[i]],
   ints[ints[ints[i]]], ..., subjected to the following rules:
1. The first element in set[i] starts with the selection of elements ints[i].
2. The next element in set[i] should be ints[ints[i]], and then ints[ints[ints[i
]]], and so on.
3. We stop adding right before a duplicate element occurs in set[i].

   Return the longest length of a set set[i].

Example 1

Input: @ints = (5, 4, 0, 3, 1, 6, 2)
Output: 4

ints[0] = 5
ints[1] = 4
ints[2] = 0
ints[3] = 3
ints[4] = 1
ints[5] = 6
ints[6] = 2

One of the longest sets set[k]:
set[0] = {ints[0], ints[5], ints[6], ints[2]} = {5, 6, 2, 0}

Example 2

Input: @ints = (0, 1, 2)
Output: 1
     __________________________________________________________________

   Last date to submit the solution 23:59 (UK Time) Sunday 22^nd December
   2024.
     __________________________________________________________________

SO WHAT DO YOU THINK ?
"""
### solution by pokgopun@gmail.com

from typing import Tuple,Dict

def na(ints: Tuple[int]) -> int:
    mx = 0
    seen = dict()
    for i in range(len(ints)):
        n = ints[i]
        while not seen.get(n,False):
            seen[n] = True
            n = ints[n]
        l = len(seen)
        if mx < l:
            mx = l
        seen.clear()
    return mx

import unittest

class TestNa(unittest.TestCase):
    def test(self):
        for inpt, otpt in {
                (5, 4, 0, 3, 1, 6, 2): 4,
                (0, 1, 2): 1,
                }.items():
            self.assertEqual(na(inpt),otpt)

unittest.main()