C# static List freqQuery(List> queries) { List result = new List(); Dictionary counts = new Dictionary();

foreach (var query in queries)
{
    int operation = query[0];
    int value = query[1];
    counts.TryGetValue(value, out int current);

    switch (operation)
    {
        case 1:
            {
                if (counts.ContainsKey(value))
                {
                    counts[value]++;
                }
                else
                {
                    counts.Add(value, current + 1);
                }
                break;
            }
        case 2:
            {
                if (current > 0)
                {
                    if (counts.ContainsKey(value))
                    {
                        counts[value]--;
                    }
                    else
                    {
                        counts.Add(value, current - 1);
                    }
                }
                break;
            }
        case 3:
            {
                var contains = counts.ContainsValue(value);
                result.Add(contains ? 1 : 0);
                break;
            }
    }
}

return result;

}