Bit Set

bitset.cs

  public class BitSet
    {
        private ulong[] bitset;
        public int Size { get; private set; }

        public BitSet(int size)
        {
            bitset = new ulong[(size / 64) + 1];
            Size = size;
        }

        public void Add(int index)
        {
            bitset[index / 64] |= (1u << (index % 64));
        }

        public bool Contains(int index)
        {
            return (bitset[index / 64] & (1u << (index % 64))) != 0;
        }
    }