PS-like

prefix sum (ps)

Ext:

https://oi-wiki.org//ds/fenwick/

https://oi-wiki.org//ds/seg/

Can Add Node

(tree)

Data relies on sub-tree

[Sack (dsu on tree)](https://litlighilit.notion.site/Sack-dsu-on-tree-2c39396db86580198850d160628dfc08)

DSU(Union-find)

N-biggest

https://oi-wiki.org//ds/dividing/