public class Solution
extends Object
1338 - Reduce Array Size to The Half\.
Medium
You are given an integer array `arr`. You can choose a set of integers and remove all the occurrences of these integers in the array.
Return _the minimum size of the set so that **at least** half of the integers of the array are removed_.
**Example 1:**
**Input:** arr = [3,3,3,3,5,5,5,2,2,7]
**Output:** 2
**Explanation:** Choosing {3,7} will make the new array [5,5,5,2,2] which has size 5 (i.e equal to half of the size of the old array).
Possible sets of size 2 are {3,5},{3,2},{5,2}.
Choosing set {2,7} is not possible as it will make the new array [3,3,3,3,5,5,5] which has a size greater than half of the size of the old array.
**Example 2:**
**Input:** arr = [7,7,7,7,7,7]
**Output:** 1
**Explanation:** The only possible set you can choose is {7}. This will make the new array empty.
**Constraints:**
* 2 <= arr.length <= 105
* `arr.length` is even.
* 1 <= arr[i] <= 105