"Think twice, code once"

Overview

I use this repository as a study playground for programming contests, which contains my personal notes and implementations. Note that this is a publish-only repository, so all pull requests will be ignored.

The folders structure is following:

• notebook: well-explained implementation of general-purpose algorithms.
• scripts: small scripts for automatizing some repetitive tasks.
• solutions: code of accepted problems, categorized by online judges.
  • README.md: solutions index by themes, containing difficulty, name, description and hint of the problem.

Notebook index

🧱 data structures

• segment tree
• lazy segment tree
• sparse table
• union-find disjoint sets (UFDS)

🥊 brute force

🔞 dynamic programming

• coin change
• subset sum
• 0-1 knapsack
• edit distance
• longest increasing subsequence (LIS)
• longest common subsequence (LCS)
  • LCS reduced to LIS
• longest palindromic subsequence (LPS)
• traveling salesman problem (TSP)
• matrix chain multiplication (MCM)
• rod cutting

🌍 graphs

• data structures representation
• traversal
  • depth-first search (DFS)
  • breadth-first search (BFS)
  • flood fill
  • edge classification
  • bridges and articulations points
  • strongly connected components (SCC)
  • topological sorting
    • kahn
    • naive
• minimum spanning tree (MST)
  • kruskal
  • variants
    • minimax path
• network flow
  • max flow w/ edmonds karp
  • min cost max flow
• shortest path
  • single-source
    • bellman ford
    • dijkstra
• specials
  • bipartite graph
    • bipartite checking
    • maximum cardinality bipartite matching
  • directed acyclic graph
  • tree
    • heavy-light decomposition (HLD)
    • lowest common ancestor (LCA)
      • binary lifting
      • eulerian tour

✏️ math

• number theory
  • fast exponentiation
  • prime numbers
    • prime checking
    • sieve of eratosthenes
    • modified sieve
    • optimized prime checking
    • prime factors of n
    • prime factors of n!
    • number of divisors of n
    • sum of divisors of n
• matrix exponentiation
  • linear recurrences
    • utility in graph
    • utility in counting

💭 miscellaneous

• binary search
• bitmasks
• two pointers

References

• HALIM, Steven. "Competitive Programming 3: The new lower bound of programming contests".