Unsorted Resources

List

• Problem List
• Problem List - SegTree - range modification + query
• Good Blog Post Resources about Algorithm and Data Structures
• All the good tutorials found for Competitive Programming
• (Plenty of) useful blogs in CodeForces

BIT

• TopCoder - BIT
• Range Update in BIT - Petr
  • Same idea can be used for storing a linear function at each index
• Fenwick tree: initialization in O(N)

HLD

• Non-Recursive HLD Implementation
• Heavy-light decompositon — it can be simple!
• Easiest HLD with subtree queries

Centroid

• Centroid Decomposition
• Centroid Decomposition of Tree
• The way to find the centroids of a tree

Policy Based

• C++ STL: Policy based data structures
• Hash Table with Policy Based Data Structures
• Policy based data structures in g++

SegTree

• using merging segment tree to solve problems about sorted list
• Compressed segment trees and merging sets in O(N logU)
• A simple introduction to “Segment tree beats”
• Persistence Made Simple - Tutorial

Math

• Tutorial Math note — Möbius inversion
• Fastest way to get factorial modulo a prime
• A problem collection of ODE and differential technique
• Tutorial Generating Functions in Competitive Programming
• Fast modular multiplication
• Linear Recurrence and Berlekamp-Massey Algorithm
• A Beautiful Technique for Some XOR Related Problems
• Basic Lagrange Interpolation
• Linear Diophantine Equations
• What is the maximum value of (a + k b) mod M?
• Matrix Exponentiation
  • Errichto also has a good video with gym questions, add it
• Inclusion-Exclusion Principle
• Tutorial on FFT/NTT - Two parts
• Tutorial Math note — Linear sieve

DP

• Cute LIS Implementation
• SOS Dynamic Programming
• A short guide to suffix automata

Convex Hull

• Online Convex Hull — queries in C++ set
• Dynamic convex hull implementation
• 3D Hull with Coplanar Points
• Efficient 3D Convex Hull Tutorial
• Tutorial Convex Hull Trick — Geometry being useful

Random numbers

• Don’t use rand(): a guide to random number generators in C++
• Blowing up unordered_map, and how to stop getting hacked on it
• How randomized solutions can be hacked, and how to make your solution unhackable
• Everything about unordered_map
• On the mathematics behind rolling hashes and anti-hash tests
• Hashing and Probability of Collision

Trees

• DFS Tree
• A slightly alternative approach for implementation of optimal LCA
• Dsu on trees (small to large)
• Sack (dsu on tree)
• 0-1 BFS
• Second Shortest Path
• Tutorial on Permutation Tree

Euler Circuit

• Algorithm on euler circuits - Codeforces
• De Bruijn sequence - Wikiwand
• C program to find Euler path or Euler Circuit
  • Problem - E - Codeforces
  • Problem - D - Codeforces

Misc

• MEX Data structure
  • See misof’s answer
• Slope trick explained
• Tutorial Matroid intersection in simple words
• How to get actual 64 bit bitsets on Codeforces
• 2-SAT Tutorial
• maximum prefix with updates ?
• Lecture #3 — Exchange arguments
• How do you polar sort?
• 2D Range Update and Query
• Difference Array
• Fractional Cascading
  • The blog contains some practice problems
  • Algorithmica Paper

• Algorithm Live : Exchange Argument
• Errichto On Codeforces : Exchange Argument

Courses

• MIT 6.046 Design and Analysis of Algorithms
• MIT 6.006 Introduction to Algorithms

Problems to upsolve

• Inversions - CodeChef
• Adding Squares - CodeChef
• Compress all Subsegments - CodeChef
• Rooted Minimum Spanning Tree - CodeChef
• Random Knapsack - CodeChef
• Village Road Network - CodeChef
• ROTATPOL - Editorial - editorial - CodeChef Discuss
• Problem - 601B - Codeforces
• Gravity Tree - Week of Code 23 Question - Contests - HackerRank
• Problem - E - Codeforces

Practice Contest

• Dashboard - 2018-2019 Summer Petrozavodsk Camp, Oleksandr Kulkov Contest 2 - Codeforces
• Dashboard - Codedigger Training Contest - Number Theory - Codeforces
• Dashboard - Codedigger Training Contest - String - Codeforces
• Dashboard - 2014 Winter Programming School, Kharkiv, day 1 (E. Kapun). High league - Codeforces
• Dashboard - 2020 Petrozavodsk Winter Camp, Jagiellonian U Contest - Codeforces
• Dashboard - 2012-2013 ACM-ICPC, NEERC, Central Subregional Contest - Codeforces
• Dashboard - Topic Stream Mashup: Trees - Codeforces
• Dashboard - Topic Stream Mashup: Probability + Combinatorics - Codeforces
• Dashboard - Algorithms Thread Treaps Contest - Codeforces
• Dashboard - CwD Educational Graph Mashup - Codeforces
• Dashboard - Number Theory Stream - Codeforces
• Dashboard - ECPC 2019 Kickoff - Codeforces
• Dashboard - 2017-2018 ACM-ICPC Southeastern European Regional Programming Contest (SEERC 2017) - Codeforces