You can prepare these-

```
Binary Search, Ternary Search
Sieve of Eratosthenes for finding primes
Segment tree (with lazy propagation)
Binary Index tree ( Also known as Fenwick Tree)
Number Theory
Heap / Priority Queue
DP
Sparse Table
KMP algorithm
Z algorithm
Aho–Corasick algorithm
Suffix Array
BFS , DFS
Union Find/Disjoint Set
Heavy-light Decomposition
Convex Hull
Network flow
Meet in the Middle
Trie
Topological Sorting
square root decomposition
Euler's Totient Function
Matrix exponentiation
Extended Euclid's algorithm
Djikstra's algorithm
Bellman-ford algorithm,
Floyd-Warshall Algorithm
Prim's Algorithm
Kruskal's Algorithm
Euler path, Euler Cycle
Articulation point
Bridges
RMQ & LCA
```

Data structure and Algorithm basics:- http://cp-algorithms.com/

**practice :-**

https://codeforces.com/gyms

https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge