Minimum Unique IDs After Removals

Problem You have a bag of ids (with duplicates) and must remove exactly m items. Return the minimum possible number of distinct ids remaining.

Input / Output

• Input: int array ids, integer m (0 <= m <= |ids|).
• Output: minimum count of distinct ids left after removing m items.

Constraints

• |ids| up to 10^5; O(n log n) expected.

Example

• ids = [2,3,1,1,1,3,4], m = 2 → 2 (remove the single 2 and the single 4; ids 1 and 3 remain).