Array Nesting
You are given an integer array nums of length n where nums is a permutation of the numbers in the range [0, n - 1].
You should build a set s[k] = {nums[k], nums[nums[k]], nums[nums[nums[k]]], ...} subjected to the following rule:
- The first element in
s[k]starts with the selection of the elementnums[k]ofindex = k. - The next element in
s[k]should benums[nums[k]], and thennums[nums[nums[k]]], and so on. - We stop adding right before a duplicate element occurs in
s[k].
Return the longest length of a set s[k].
Example 1
Input
nums = [5,4,0,3,1,6,2]Output
4One of the longest sets is
s[0] = {nums[0], nums[5], nums[6], nums[2]} = {5, 6, 2, 0}, which has length 4.Example 2
Input
nums = [0,1,2]Output
1Each set stops immediately before repeating its starting value, so the longest length is 1.
Constraints
- 1 <= nums.length <= 10^5
- 0 <= nums[i] < nums.length
- All the values of nums are unique.