Add Heavy Light Decomposition

[WeakGT]

• Introduce to Heavy Light Decomposition

  • Intro
  • Definition of Heavy Node and Light Node

• Properties

  • All nodes belong to a heavy chain
  • Complete Decomposition
  • dfs time stamp is continuous

• Implementation

  • dfs first time to record father, deep, size, heavy node
  • dfs second time to construct heavy chain and light chain
  • Build data structures on each heavy chain
  • Queries
  • Definition of variables and code

• Prove the time complexity

• Problems

• Reference

  • https://oi-wiki.org/graph/hld/
  • https://codeforces.com/blog/entry/81317
  • https://cp-algorithms.com/graph/hld.html