Nikita and LCM

brute force, data structures, dp, greedy, math, number theory, sortings

Mind Bloom

dp

Set

bitmasks, brute force, combinatorics, dfs and similar, divide and conquer, dp, math

Money Buys Happiness

dp

Maximum GCD Sum Queries

bitmasks, brute force, dp, implementation, number theory

Min-Fund Prison (Hard)

bitmasks, dfs and similar, dp, graphs, trees

Min-Fund Prison (Medium)

brute force, dfs and similar, dp, graphs, trees

Trails (Hard)

dp, matrices

Trails (Medium)

dp, matrices

Trails (Easy)

dp

Game on Tree (Hard)

dfs and similar, dp, games, trees

Card Pairing

dp, greedy, hashing, implementation

Unique Array

binary search, data structures, divide and conquer, dp, greedy

Division + LCP (hard version)

binary search, brute force, data structures, dp, hashing, math, string suffix structures, strings

Division + LCP (easy version)

binary search, data structures, dp, hashing, string suffix structures, strings

Again Counting Arrays (Hard Version)

combinatorics, dp, math

Again Counting Arrays (Easy Version)

combinatorics, dp, fft, math

Fenwick Tree

bitmasks, brute force, combinatorics, data structures, dp, math, trees

Composite Spells

*special problem, dp

Carousel of Combinations

brute force, combinatorics, dp, math, number theory

A BIT of an Inequality

bitmasks, brute force, dp, math

Nene and the Mex Operator

bitmasks, brute force, constructive algorithms, divide and conquer, dp, greedy, implementation, math

The Most Reckless Defense

bitmasks, brute force, constructive algorithms, dp, flows, graph matchings, shortest paths

GCD on a grid

brute force, dfs and similar, dp, implementation, math, number theory

Unfair Game

dp, games, greedy, math, schedules

Unique Strings

combinatorics, dp, math

Colored Balls

combinatorics, dp, math, sortings

Thanos Snap

binary search, dp, games, greedy, trees

Shuffling Songs

bitmasks, dfs and similar, dp, graphs, hashing, implementation, strings

Annual Ants' Gathering

dfs and similar, dp, greedy, trees

Grove

brute force, dfs and similar, dp, geometry, probabilities

Nobody is needed

2-sat, data structures, dfs and similar, dp

Girl Permutation

combinatorics, dp, math, number theory

Minimum Hamming Distance

dp

Counting Is Fun (Hard Version)

combinatorics, dp

Counting Is Fun (Easy Version)

brute force, combinatorics, dp, math

Farmer John's Favorite Intern

data structures, dp, flows, trees

Bessie and Cards

combinatorics, dp, math

Learning to Paint

binary search, data structures, dfs and similar, dp, greedy, implementation, sortings

Messenger in MAC

binary search, brute force, constructive algorithms, data structures, dp, greedy, sortings

Turtle Mission: Robot and the Earthquake

dfs and similar, dp, graphs, shortest paths

Feed Cats

data structures, dp, sortings

Prefix Max Set Counting

data structures, dp, trees

2..3...4.... Wonderful! Wonderful!

combinatorics, dp, math

Sum over all Substrings (Hard Version)

bitmasks, divide and conquer, dp, dsu, greedy, implementation, strings

Sum over all Substrings (Easy Version)

brute force, dp, greedy, strings

Sasha and the Happy Tree Cutting

bitmasks, brute force, dfs and similar, dp, graphs, greedy, math, trees

Sasha and a Walk in the City

combinatorics, dp, math, trees

Modular Sequence

brute force, constructive algorithms, dp, graphs, greedy, math, number theory

Paint Charges

data structures, dp, greedy, math

Vlad and Trouble at MIT

dfs and similar, dp, flows, graphs, greedy, implementation, trees

Vlad and Avoiding X

bitmasks, brute force, dfs and similar, dp, implementation

Good Trip

combinatorics, dp, math, probabilities

Anti-Proxy Attendance

constructive algorithms, dp, interactive, ternary search

Balanced Subsequences

combinatorics, dp, math

Count Paths

data structures, dfs and similar, dp, dsu, graphs, trees

Replace on Segment

dp, graph matchings

Mischievous Shooter

brute force, data structures, divide and conquer, dp, implementation

Sum of Progression

brute force, data structures, dp, implementation, math

Counting Binary Strings

combinatorics, dp, math

Wine Factory (Hard Version)

data structures, dp, flows, greedy, matrices

Counting Prefixes

combinatorics, constructive algorithms, dp, implementation, math

Blocking Elements

binary search, data structures, dp, implementation, two pointers

Construct Tree

bitmasks, constructive algorithms, dp, trees

Yet Another Inversions Problem

combinatorics, data structures, dp, implementation, math, number theory

Matrix Rank (Hard Version)

combinatorics, dp, math, matrices, string suffix structures

Matrix Rank (Easy Version)

brute force, combinatorics, dp, math, matrices

Optimizations From Chelsu

divide and conquer, dp, number theory, trees

Light Bulbs (Hard Version)

combinatorics, data structures, dfs and similar, dp, graphs, hashing

Light Bulbs (Easy Version)

brute force, combinatorics, dfs and similar, dp, dsu, graphs, math, trees

Programming Competition

dfs and similar, dp, graph matchings, greedy, trees

Array Collapse

data structures, divide and conquer, dp, trees

Kim's Quest

bitmasks, combinatorics, dp

Inverse Problem

*special problem, combinatorics, dp

Maximum Sum Subarrays

*special problem, dp

Short Permutation Problem

combinatorics, dp, fft, math

Small Permutation Problem (Hard Version)

combinatorics, dp, math

Small Permutation Problem (Easy Version)

brute force, combinatorics, dp, math

Count BFS Graph

combinatorics, dp

Twin Friends

combinatorics, dp

Merge Not Sort

constructive algorithms, dp

One-X

combinatorics, dfs and similar, dp, math, trees

Maximum And Queries (hard version)

bitmasks, divide and conquer, dp, greedy

Robot Queries

binary search, data structures, dp, implementation

Compressed Tree

dfs and similar, dp, graphs, greedy, sortings, trees

Transitive Graph

dfs and similar, dp, dsu, graphs, implementation

Small GCD

bitmasks, brute force, dp, math, number theory

Cyclic Hamming (Hard Version)

brute force, dp, fft, math, number theory

Cyclic Hamming (Easy Version)

brute force, divide and conquer, dp, fft, math, number theory

Two Characters, Two Colors

binary search, data structures, dp, flows, greedy

Fancy Arrays

combinatorics, dp, math, matrices

Infinite Card Game

binary search, brute force, data structures, dfs and similar, dp, dsu, games, graphs, greedy, sortings, two pointers

Cacti Symphony

combinatorics, dfs and similar, dp, graphs

Doremy's Average Tree

data structures, dp, greedy, trees

Doremy's Drying Plan (Hard Version)

data structures, dp

Doremy's Drying Plan (Easy Version)

brute force, data structures, dp, greedy, sortings

I Wanna be the Team Leader

bitmasks, constructive algorithms, dp, greedy, math, sortings, two pointers

Counting Rhyme

dp, math, number theory

Tree XOR

bitmasks, dfs and similar, dp, greedy, trees

Ball-Stackable

constructive algorithms, data structures, dp, trees