Competitive Programming

Solutions

Codeforces
LeetCode

Data Structures

• Fenwick Tree
• Union-Find (Disjoint Set)

Reference

• Algorithms

  • Rosetta Code
  • CP-Algorithms
  • KACTL
  • Codeforces
  • Hackerearth
  • Algorithms, Part I, Algorithms, Part II
  • Top 10 Algorithms and Data Structures for Competitive Programming
  • Algorithms for Competitive Programming
  • Algorithms Weekly by Petr Mitrichev

• Math

  • Stack Exchange

• Visualization

  • Data Structure Visualizations
  • Algorithm Visualizer
  • VisuAlgo

• Top YouTube Channels

  • Tushar Roy - Coding Made Simple
  • WilliamFiset
  • Algorithms Live!
  • take U forward

• Misc

  • Thinking Techniques as follows:

n	Complexity	Possible Algorithms & Techniques
1018+	O(1)	Math
1018	O(logn)	Binary & Ternary Search / Matrix Power / Cycle Tricks / Big Simulation Steps / Values Reranking / Math
1016	O(n1/2)	Math
108	O(n)	Greedy / Ad-hoc / DP
4×107	O(nlogn)	Linear # Calls to Binary & Ternary Search / Pre-processing & Querying / Divide and Conquer
104	O(n2)	Ad-hoc / DP / Greedy / Divide and Conquer / Branch and Bound
500	O(n3)	Ad-hoc / DP / Greedy / Divide and Conquer / Branch and Bound
90	O(n4)	Ad-hoc / DP / Greedy / Divide and Conquer / Branch and Bound
50	O(n5)	Branch and Bound
40	O(n×2n/2)	Meet in the Middle
20	O(n×2n)	Backtracking / Generating 2n Subsets / Bitmask Technique
11	O(n!)	Factorial / Permutation / Combination Algorithm