- Difficulty: Medium
- Tags: LeetCode, Medium, Union Find, Counting, Interactive, leetcode-2782, Array, O(n^2), O(1), 🔒, Brute Force
Problem
You are given an integer n
and an object categoryHandler
of class CategoryHandler
.
There are nÂ
elements, numbered from 0
to n - 1
. Each element has a category, and your task is to find the number of unique categories.
The class CategoryHandler
contains the following function, which may help you:
boolean haveSameCategory(integer a, integer b)
: Returnstrue
ifa
andb
are in the same category andfalse
otherwise. Also, if eithera
orb
is not a valid number (i.e. it's greater than or equal ton
or less than0
), it returnsfalse
.
Return the number of unique categories.
Â
Example 1:
Input: n = 6, categoryHandler = [1,1,2,2,3,3] Output: 3 Explanation: There are 6 elements in this example. The first two elements belong to category 1, the second two belong to category 2, and the last two elements belong to category 3. So there are 3 unique categories.
Example 2:
Input: n = 5, categoryHandler = [1,2,3,4,5] Output: 5 Explanation: There are 5 elements in this example. Each element belongs to a unique category. So there are 5 unique categories.
Example 3:
Input: n = 3, categoryHandler = [1,1,1] Output: 1 Explanation: There are 3 elements in this example. All of them belong to one category. So there is only 1 unique category.
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Constraints:
1 <= n <= 100