You are iterating the map for finding whether the required frequency is present or not. Try maintaining the frequency to values map. So you won't have to iterate the map. see below code :-

static List freqQuery(List queries) { List result = new ArrayList<>(); Map operationsMap = new HashMap();

    Map<Integer, Set<Integer>> frequencyMap = new HashMap<>();
    for (int[] query : queries) {
        switch (query[0]) {
        case 1:
            Integer m = operationsMap.get(query[1]);
            if (m == null) {
                operationsMap.put(query[1], 1);
                Set<Integer> sampleMap = frequencyMap.get(1);
                if (sampleMap != null)
                    sampleMap.add(query[1]);
                else
                    frequencyMap.put(1, new HashSet() {
                        {
                            add(query[1]);
                        }
                    });
            } else {
                operationsMap.put(query[1], ++m);
                frequencyMap.get(m - 1).remove(query[1]);
                Set<Integer> sampleMap = frequencyMap.get(m);
                if (sampleMap != null)
                    sampleMap.add(query[1]);
                else
                    frequencyMap.put(m, new HashSet() {
                        {
                            add(query[1]);
                        }
                    });
            }

            break;
        case 2:
            Integer n = operationsMap.get(query[1]);
            if (n == null)
                break;
            else if (n == 1) {
                operationsMap.remove(query[1]);
                frequencyMap.get(1).remove(query[1]);
            } else {
                operationsMap.put(query[1], --n);
                frequencyMap.get(n + 1).remove(query[1]);
                Set<Integer> sampleMap = frequencyMap.get(n);
                if (sampleMap != null)
                    sampleMap.add(query[1]);
                else
                    frequencyMap.put(n, new HashSet() {
                        {
                            add(query[1]);
                        }
                    });

            }
            break;
        case 3:
            result.add((frequencyMap.get(query[1]) == null || frequencyMap.get(query[1]).isEmpty()) ? 0 : 1);
            break;
        }
    }

return result; }