Reference

• Self-adjusting top trees by Robert E. Tarjan et al.
• https://negiizhao.blog.uoj.ac/blog/4912 by negiizhao.
• https://www.cnblogs.com/HolyK/p/14332568.html by HolyK.
• https://github.com/ecnerwala/cp-book/blob/master/src/top_tree.hpp