Question

I am sorting a Dictionary of 10,000 elements using the OrderBy method as shown below and want to know the big O of it. Does anyone know? After Ordering them I then add them to a new Dictionary in that order. There might be a better way of doing this, but it works for my purposes.

Here is my example:

        m_sortedItems = new Dictionary<int,string>();
        foreach(KeyValuePair<int,string> item in collection.OrderBy(key => key.Value)){
            m_sortedItems.Add(item.Key, item.Value);
        }

I checked on msdn but it wasn’t listed:
http://msdn.microsoft.com/en-us/library/bb534966.aspx

Answer 1

A Dictionary does not have defined order, so adding items in a particular order is not something that you should be doing.

As far as the big O of sorting, O(NlogN) is going to be the benchmark for most sorting algorithms that you will come across.