public void Add(T first, T second)
{
Dictionary <T, int> InnerMap;
if (!Chain.ContainsKey(first))
{
InnerMap = new Dictionary <T, int>();
InnerMap.Add(second, 0);
Chain.Add(first, InnerMap);
}
else
{
InnerMap = Chain[first];
}
if (!InnerMap.ContainsKey(second))
{
InnerMap.Add(second, 0);
}
int weight = InnerMap[second];
InnerMap.Remove(second);
InnerMap.Add(second, weight + 1);
}