Hi all of you. here is some very common algorithms in the form of class. writing those in contests was waste of time so you just need copy and paste the class (modify as per your need) ans use it.

DSU (disjoint Set Union)

Fenwick tree

Binary trie

Convex hull

Manachers's algorithms

String hashing

Matching

Dinic (Maximum flow)

Segment Tree and Lazy Propagation

Max-Min Spanning tree

Tree (dfs, bfs, lca, diameter)

HLD (heavy light decomposition with Segment Tree and Lazy Propagation

Graph (bridges, check cycle)