1481-least-number-of-unique-integers-after k-removals.js

// 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


const findLeastNumOfUniqueInts = function (arr, k) {
    const map = {}
  
    for (const num of arr) {
      map[num] = map[num] || 0
      map[num] += 1
    }
    const keys = Object.keys(map).sort((a, b) => map[a] - map[b])
    for (const key of keys) {
      while (map[key] > 0 && k > 0) {
        k--
        map[key] -= 1
        if (map[key] === 0) {
          delete map[key]
        }
      }
    }
    return Object.keys(map).length
}