Indexator

public int this[T from, T to]
        {
            get
            {
                if (_adjacencyList[from].ContainsKey(to))
                {
                    return _adjacencyList[from][to];
                }
                else
                {
                    return Int32.MaxValue;
                }
            }
            set
            {
                _adjacencyList[from][to] = value;
            }
        }