public class Solution
extends Object
1481 - Least Number of Unique Integers after K Removals\.
Medium
Given an array of integers `arr` and an integer `k`. Find the _least number of unique integers_ after removing **exactly** `k` elements**.**
**Example 1:**
**Input:** arr = [5,5,4], k = 1
**Output:** 1
**Explanation:** Remove the single 4, only 5 is left.
**Example 2:**
**Input:** arr = [4,3,1,1,3,3,2], k = 3
**Output:** 2
**Explanation:** Remove 4, 2 and either one of the two 1s or three 3s. 1 and 3 will be left.
**Constraints:**
* `1 <= arr.length <= 10^5`
* `1 <= arr[i] <= 10^9`
* `0 <= k <= arr.length`