Description of Change

Checklist

• Added description of change
• Added file name matches [File

There are 2 places we are using BufferBlock<T> today:

https://github.com/dotnet/machinelearning/blob/b7db4fa475ba4bd52824eb98bbf5f5bf4a0a6f7a/src/Microsoft.ML.Data/Transforms/RowShufflingTransformer.cs#L486-L487

https://github.com/dotnet/machinelearning/blob/b7db4fa475ba4bd52824eb98bbf5f5bf4a0a6f7a/src/Microsoft.ML.Sweeper/AsyncSweeper.cs#L171

We should consider replacing this depende

Add quickselect algorithm. Quickselect is a selection algorithm to find the kth smallest element in an unordered list.

Description of Change

1. adding new feature - articulation point algorithm. In a graph, a vertex is called an articulation point if removing it and all the edges associated with it results in the increase of the number of connected components in the graph. For example consider the graph given in following figure.
2. moving the GraphRep struct from Graph.c to Graph.h

References

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steps to reproduce

Write a loop, from 1 to 80000, each time add a random int to the max heap.

In theory it takes very little time(NlogN, N=80000, <1sec ), but the program does take a long time.

I'v also tested the BinaryHeap in https://github.com/SolutionsDesign/Algorithmia, it performs well, so it is probably due to the bad algorithm.