Program to find least number of unique integers after K removals using Python

Suppose we have an array called nums where only integers are stored. If we have a number k. We have to find least number of unique elements after removing exactly k elements.

So, if the input is like nums = [5,4,2,2,4,4,3], k = 3, then the output will be 2, because if we remove 5 and 3, and either any one of 2s or any one of 4s, then there only 2 and 4 will be left.

To solve this, we will follow these steps −

• dictionary:= a new map

• for each num in nums, do

  • if num is not in dictionary, then

    • dictionary[num]:= 1

  • otherwise,

    • dictionary[num] := dictionary[num] + 1

• count:= size of dictionary

• for each frequency in the sorted order of all values of dictionary, do

  • k := k - frequency

  • if k < 0, then

    • return count

  • otherwise,

    • count := count - 1

• return count

Let us see the following implementation to get better understanding −

Example

 Live Demo

def solve(nums, k):
   dictionary={}
   for num in nums:
      if num not in dictionary:
         dictionary[num]=1
      else:
         dictionary[num]+=1
   count=len(dictionary)
   for frequency in sorted(dictionary.values()):
      k-=frequency
      if(k<0):
         return count
      else:
         count-=1
   return count
nums = [5,4,2,2,4,4,3]
k = 3
print(solve(nums, k))

Input

[5,4,2,2,4,4,3], 3

Output

2