算法：在一组集合中，取得第K小的值

class Calculate<T>
{
public List<List<T>> Lists;

public Calculate(List<List<T>> _Lists)
{
Lists = _Lists;
}

private List<T> UnionLists()
{
List<T> results = new List<T>();
for (int i = 0; i < Lists.Count; i++)
{
for (int j = 0; j < Lists[i].Count; j++)
{
results.Add(Lists[i][j]);
}
}
results.Sort();
results = results.Distinct().ToList(); ;
return results;
}

public T getIndex(int K)
{
List<T> results = UnionLists();
return results.ElementAt(K-1);
}

}

List<int> list1 = new List<int> { 5, 6, 10 };
List<int> list2 = new List<int> { 5, 6, 10 };
List<int> list3 = new List<int> { 8, 9, 12 };
List<int> list4 = new List<int> { 9, 13, 15 };
List<List<int>> list = new List<List<int>> { list1,list2,list3,list4};
Calculate<int> cal = new Calculate<int>(list);
Console.WriteLine(cal.getIndex(4));
Console.ReadLine();