Concepts3

DSU on Tree (Sack)

DSU on Tree (also called the Sack technique) answers many subtree queries in O(n \log n) by keeping data from the heavy child and temporarily re-adding light subtrees.

#dsu on tree#sack technique#subtree queries+12

⚙️AlgorithmAdvanced

Knuth Optimization

Knuth Optimization speeds up a class of interval dynamic programming (DP) from O(n^3) to O(n^2) by exploiting the monotonicity of optimal split points.

#knuth optimization#interval dp#quadrangle inequality+12

🗂️Data StructureAdvanced

Centroid Decomposition - Distance Queries

Centroid decomposition splits a tree into levels by repeatedly removing a centroid so that each remaining component is at most half the size.

#centroid decomposition#tree distance queries#nearest red node+12