Topic Wise Competitive Programming Problems.

 Z-algorithm:

•  https://codeforces.com/contest/432/problem/D
•  https://codeforces.com/contest/1537/problem/E2
•  https://codeforces.com/contest/126/problem/B
•  https://codeforces.com/contest/149/problem/E

Binary Search:

•  https://codeforces.com/contest/432/problem/C
•  https://codeforces.com/contest/1530/problem/C
•  https://codeforces.com/contest/1619/problem/D
•  https://codeforces.com/contest/1624/problem/F
•  https://codeforces.com/contest/1661/problem/C
•  https://codeforces.com/contest/1712/problem/D
•  bs+range query
•  simulate and find pattern
•  So much tight TL

DFS:

•  https://codeforces.com/contest/1209/problem/D
•  https://codeforces.com/contest/1167/problem/C
•  https://codeforces.com/contest/1537/problem/F
•  https://codeforces.com/contest/505/problem/B
•  https://codeforces.com/problemset/problem/24/A
•  smart work with dfs tree

BFS:

•  https://codeforces.com/contest/1638/problem/D
•  4 node is enough to store
•  Multisource BFS xoss problem
•  0-1 bfs + super optimazation with observation
•  actually there is no cycle

DSU:

•  https://codeforces.com/contest/1167/problem/C
•  https://codeforces.com/contest/982/problem/D
•  https://codeforces.com/contest/1609/problem/D
•  https://codeforces.com/contest/1620/problem/E
•  https://toph.co/p/hashing
•  https://codeforces.com/problemset/problem/1691/E
•  Odd sized groups
•  group size is important
•  Convert it to a RmxQ problem
•  Weighted DSU

Dynamic Programming:

•  https://codeforces.com/problemset/problem/189/A
•  https://codeforces.com/contest/1132/problem/F
•  https://codeforces.com/contest/895/problem/C
•  https://codeforces.com/problemset/problem/118/D
•  https://lightoj.com/problem/a-refining-company
•  https://codeforces.com/problemset/problem/431/C
•  https://codeforces.com/problemset/problem/474/D
•  https://codeforces.com/problemset/problem/711/C
•  https://lightoj.com/problem/bar-codes
•  https://codeforces.com/contest/505/problem/C
•  https://codeforces.com/problemset/problem/1508/B
•  https://codeforces.com/contest/204/problem/A
•  https://atcoder.jp/contests/abc222/tasks/abc222_d
•  https://codeforces.com/contest/1593/problem/F
•  https://codeforces.com/contest/1581/problem/C
•  https://codeforces.com/contest/1582/problem/F2
•  https://codeforces.com/contest/1579/problem/F
•  https://codeforces.com/problemset/problem/1575/D
•  https://codeforces.com/contest/1609/problem/C
•  https://codeforces.com/contest/1614/problem/D1
•  https://codeforces.com/contest/1613/problem/D
•  https://codeforces.com/contest/1207/problem/C
•  https://algo.codemarshal.org/contests/icpc-dhaka-20-preli/problems/G
•  https://codeforces.com/contest/1624/problem/E
•  https://codeforces.com/contest/1635/problem/D
•  CF- D. XOR-pyramid
•  WITH MONOTONUS QUEUE
•  https://toph.co/p/switchblade-of-thanos
•  https://codeforces.com/contest/1680/problem/E
•  SOS dp
•  https://www.codechef.com/problems/SONGSHOP
•  dp+bs+cycle detection
•  dp+totient
•  dp+binary tree
•  dp+prefix sum
•  dp+greedy+bitmasking
•  https://codeforces.com/contest/1699/problem/D
•  DP+map
•  Only iterative and memory optimization
•  DP+hashing
•  super ovservation
•  prefix sum+bs+number theory
•  Optimization with unique value and Binary.
•  seem bipartite coloring but not
•  divide and conquer
•  Simple but cool
•  gcd
•  make strictly increasing or decreasing
•  dp in dense graph
•  Optimal Cycle Finding
•  Optimazation using segtree
•  sqrt memorize in a tree
•  think reverse
•  Next is at most current max minus one
•  monotic queue eliminates log(n)
•  Exchange arg+ Optimization using constraints
•  Every bit separately
•  Great optimization using bitset
•  Number of LIS
•  Exchange Argument is cool
•  Game turns into equal subsequence DP
•  Heavy Precision Handling
•  Nice Knapsack
•  Nice work with ancestor. time limit 7s!
•  Nice one to learn dp with ds
•  work with the edge array
•  Arithmatic Progression

Inclusion/Exclusion:

•  https://lightoj.com/problem/helping-cicada
•  https://codeforces.com/problemset/problem/1295/D
•  https://codeforces.com/contest/1750/problem/D
•  sorting + combinatorics
•  dearrangement

Centroid of tree:

•  https://codeforces.com/contest/1406/problem/C

Combinatorics:

•  https://codeforces.com/contest/1546/problem/D
•  https://codeforces.com/contest/1699/problem/C

Minimum Spanning Tree:

•  https://lightoj.com/problems/category/mst
•  https://codeforces.com/contest/1624/problem/G
•  https://codeforces.com/contest/1688/problem/E

Segment Tree:

•  https://codeforces.com/problemset/problem/1547/F
• https://toph.co/p/a-unique-array
•  https://codeforces.com/contest/1661/problem/D
•  https://toph.co/p/maximum-distance
•  Good use of lazy in bracket seq.
•  Artihmatic Progression

Sparse Table:

•  https://codeforces.com/contest/863/problem/
•  https://codeforces.com/contest/1611/problem/F
•  sparse table+bfs+bs
•  RmxQ

Scanline Algorithm:

•  https://codeforces.com/problemset/problem/295/A
•  https://codeforces.com/contest/1343/problem/D
•  https://codeforces.com/problemset/problem/816/B

Euler Totient:

•  https://codeforces.com/problemset/problem/1295/D
•  Becomes 1 in at most 23 operations.

Hashing:

•  https://algo.codemarshal.org/contests/icpc-dhaka-20-preli/problems/G
•  https://codeforces.com/contest/1657/problem/C
•  Tree Hashing
•  Xor Hashing

LCA:

•  https://codeforces.com/contest/1328/problem/E
•  LCA and Range query
•  LCA +mst

BINARY INDEXED TREE:

•  https://codeforces.com/contest/1585/problem/D
•  https://codeforces.com/contest/1660/problem/F2

TOPOLOGICAL SORT:

•  https://codeforces.com/contest/510/problem/C
•  indegree method must

BIPARTITE GRAPH:

•  https://codeforces.com/contest/862/problem/B
•  Intersecting segments

TRIE TREE:

•  https://codeforces.com/contest/455/problem/B
•  https://codeforces.com/contest/1658/problem/D2
•  https://codeforces.com/contest/706/problem/D
•  Nice combo of trie and NT

MONOTONIC QUEUE:

•  https://codeforces.com/contest/1195/problem/E
•  https://toph.co/p/birthday-present-2 (WITH DP)

Expected Value:

•  https://codeforces.com/contest/846/problem/F

KMP:

•  https://codeforces.com/contest/1138/problem/D

Prime Factorization:

•  Parity of the prime

Bitset:

•  And operation
•  String matching
•  custom bitset and custom sized bitset

Number Theory:

•  lcm
•  prime factorization+nod+overflow handling
•  https://toph.co/p/powerful-number
•  Mobius
•  Cool Application of Mobius

Mo's Algorithm:

•  xor prefix
•  Tight time
•  also dsu on tree

Sqrt Decomposition:

•  block size should be sqrt(n)+1

Suffix Array:

•  work with lcp
•  good use of lcp

Dense Graph:

•  Say to to always kruskal

Floyd Warshall:

•  Feel the ALgo
•  Super Source

Meet in the Middle:

•  Feel the ALgo
•  binary seach with it

Palindromic Tree:

•  eerTree and Hashing
•  Problem M. Leveling

DSU on Tree:

•  Also Mo's

Compiler Optimization:

•  memory also
•  toph

Compiler Optimization:

•  Bs in tree

Strongly Connected Components:

•  BS and topsrt included

Matrix Multiplication:

•  Mod is not always prime

Mo's on Tree:

•  Unique Numbers
•  Problem F with super optimization using SQRT decomposition

Binary Lifting:

•  MSB concept
•  Convert this to a tree

Bitmask:

•  So tight time limit

Bellman-Ford:

•  Add extra Node

Pigeonhole Principle:

•  three

Stack:

•  Both side are important
•  easy one side included
•  Problem G.

Geometry:

•  Easy

Geometry:

•  Easy

Dijkstra:

•  Convert it to dijkstra
•  The coolest dijkstra problem

Difference Array:

•  Coolest One

XOR Basis:

•  +LCA

Educational Problems:

•  Find to set x and y such that x is not a subset of y

Min cost max flow:

•  How to handle grid