575. Distribute Candies

Description

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

Approach

Links

• GeeksforGeeks

• Leetcode

• ProgramCreek

• YouTube

Examples

Example 1

Input: candyType = [1, 1, 2, 2, 3, 3]

Output: 3

Explanation: Alice can only eat 6 / 2 = 3 candies. Since there are only 3 types, she can eat one of each type.

Example 2

Input: candyType = [1, 1, 2, 3]

Output: 2

Explanation: Alice can only eat 4 / 2 = 2 candies. Whether she eats types [1, 2], [1, 3], or [2, 3], she still can only eat 2 different types.

Example 3

Input: candyType = [6, 6, 6, 6]

Output: 1

Explanation: Alice can only eat 4 / 2 = 2 candies. Even though she can eat 2 candies, she only has 1 type.

Solutions

Solution 1

/**
 * Time complexity : Adding an item into a Hash Set has an amortized 
 *    time of O(1).Therefore, adding N items requires O(N) time. 
 *    All of the other operations we use are O(1).
 * Space complexity : The worst case for space complexity occurs when all 
 *    N elements are unique. This will result in a Hash Set containing N elements.
 */

class Solution {
    public int distributeCandies(int[] candyType) {
        Set<Integer> uniqueCandies = new HashSet();
        
        for(int candy: candyType) {
            uniqueCandies.add(candy);
        }
        
        return Math.min(uniqueCandies.size(), candyType.length/2);
    }
}

Follow up