Problem
Alice has n
candies, where the ith
candy is of type candyType[i]
. Alice noticed that she started to gain weight, so she visited a doctor.
The doctor advised Alice to only eat n / 2
of the candies she has (n
is always even). Alice likes her candies very much, and she wants to eat the maximum number of different types of candies while still following the doctor’s advice.
Given the integer array candyType
of length n
, return the maximum number of different types of candies she can eat if she only eats n / 2
of them.
Examples
Example 1:
|
|
Example 2:
|
|
Example 3:
|
|
Constraints:
n == candyType.length
2 <= n <= 104
n
is even.-105 <= candyType[i] <= 105
Solution
Method 1 – Hash Set for Unique Types
Intuition
The key idea is that Alice can eat at most n/2
candies, but she wants to maximize the number of different types. The answer is the minimum of the number of unique types and n/2
. For example, if there are 3 unique types and she can eat 3 candies, she can eat all types. If there are 4 unique types but she can only eat 2 candies, she can only eat 2 types.
Approach
- Count the number of unique candy types using a set or hash table.
- Calculate
n/2
, wheren
is the total number of candies. - The answer is the minimum of the number of unique types and
n/2
.
C++
|
|
Java
|
|
Python
|
|
Complexity
- ⏰ Time complexity:
O(N)
, whereN
is the number of candies. - 🧺 Space complexity:
O(K)
, whereK
is the number of unique candy types.