Question 1
You are shopping online for some bags of onion. Each listing displays the number of onions that the bag contains. You want to buy a perfect set of onion bags from the entire search results list, onionBags. A perfect set of onion bags, perfect, is defined as:
- The set contains at least two bags of onion.
- When the onion bags in the set perfect are sorted in increasing order by count, it satisfies the condition perfect[i]
perfect[i] = perfect[i+1] for all 1 ≤ i < n. Here n is the size of the set and perfect[i] is the number of onion in bag i.
Find the largest possible set perfect and return an integer, the size of that set. If no such set is possible, then return -1. It is guaranteed that all elements in onionBags are distinct.
Example
Let the bags of onion available online have counts [3, 9, 4, 2, 16]. The following are the perfect sets.
- Set perfect = [3, 91]. The size of this set is 2.
- Set perfect = [4, 2]. The size of this set is 2.
- Set perfect = [4, 16]. The size of this set is 2
- Set perfect = [4, 2, 16]. The size of this set is 3.
The size of the largest set is 3. The image below illustrates the correct ordering of the purchased onion bags by count.