This work is a implementation based on 2018 IEEE paper "Scalable K-Core Decomposition for Static Graphs Using a Dynamic Graph Data Structure".

Previously we found all vertices with degree peel = 1, and delete them with their incident edges from G.

Now, however, we do not delete the vertices and edges. Instead, when we find a vertex u, we flag u and decrement the degree of u and all of u’s neighbors. Vertices that are flagged are not considered to be present in G, although they are not explicitly deleted.

• K-Core Decomposition of Large Networks on a Single PC

  https://dl.acm.org/doi/pdf/10.14778/2850469.2850471

• A Distributed k-Core Decomposition Algorithm on Spark

  https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8258018

• Scalable K-Core Decomposition for Static Graphs Using a Dynamic Graph Data Structure

  https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8622056