Array Nesting Python Solution with Tests

lcpy gen -n 565   # by problem number
lcpy gen -s array_nesting   # by problem name

Input: nums = [5,4,0,3,1,6,2]
Output: 4
Explanation: nums[0] = 5, nums[1] = 4, nums[2] = 0, nums[3] = 3, nums[4] = 1, nums[5] = 6, nums[6] = 2.
One of the longest sets s[k]:
s[0] = {nums[0], nums[5], nums[6], nums[2]} = {5, 6, 2, 0}

Input: nums = [0,1,2]
Output: 1

class Solution:
    # Time: O(n) - each index is visited exactly once across all cycles
    # Space: O(1) - marks visited in place, no extra set
    def array_nesting(self, nums: list[int]) -> int:
        best = 0
        for i in range(len(nums)):
            if nums[i] < 0:
                continue
            count = 0
            j = i
            while nums[j] >= 0:
                nxt = nums[j]
                nums[j] = -1
                j = nxt
                count += 1
            best = max(best, count)
        return best