Distribute Candies

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.

Constraints

• n == candyType.length
• 2 <= n <= 104
• n is even.
• -105 <= candyType[i] <= 105

Solution

The problem Distribute Candies can be solved using a bitset as a hashmap to check the total number of different types of candies. In case the number of different types of candies exceeds n / 2, then n / 2 becomes the maximum number of different types of candies Alice can eat.

Implementation

class Solution
{
  public:
    int distributeCandies(vector<int> &candyType)
    {
        bitset<200001> bits;
        for (int type : candyType)
            bits.set(type + 100000);

        return min(bits.count(), candyType.size() / 2);
    }
};