Design a data structure that keeps track of the values in it and answers some queries regarding their frequencies.
Implement the FrequencyTracker class.
FrequencyTracker(): Initializes the FrequencyTracker object with an empty array initially.void add(int number): Adds number to the data structure.void deleteOne(int number): Deletes one occurrence of number from the data structure. The data structure may not contain number, and in this case nothing is deleted.bool hasFrequency(int frequency): Returns true if there is a number in the data structure that occurs frequency number of times, otherwise, it returns false.Example 1:
Input ["FrequencyTracker", "add", "add", "hasFrequency"] [[], [3], [3], [2]] Output [null, null, null, true] Explanation FrequencyTracker frequencyTracker = new FrequencyTracker(); frequencyTracker.add(3); // The data structure now contains [3] frequencyTracker.add(3); // The data structure now contains [3, 3] frequencyTracker.hasFrequency(2); // Returns true, because 3 occurs twice
Example 2:
Input ["FrequencyTracker", "add", "deleteOne", "hasFrequency"] [[], [1], [1], [1]] Output [null, null, null, false] Explanation FrequencyTracker frequencyTracker = new FrequencyTracker(); frequencyTracker.add(1); // The data structure now contains [1] frequencyTracker.deleteOne(1); // The data structure becomes empty [] frequencyTracker.hasFrequency(1); // Returns false, because the data structure is empty
Example 3:
Input ["FrequencyTracker", "hasFrequency", "add", "hasFrequency"] [[], [2], [3], [1]] Output [null, false, null, true] Explanation FrequencyTracker frequencyTracker = new FrequencyTracker(); frequencyTracker.hasFrequency(2); // Returns false, because the data structure is empty frequencyTracker.add(3); // The data structure now contains [3] frequencyTracker.hasFrequency(1); // Returns true, because 3 occurs once
Constraints:
1 <= number <= 1051 <= frequency <= 1052 * 105 calls will be made to add, deleteOne, and hasFrequency in total.NeetCode