Red-Blue Operations (Easy Version)

binary search, greedy, implementation, math

LuoTianyi and the Floating Islands (Hard Version)

combinatorics, dfs and similar, math, probabilities, trees

Magic Triples (Hard Version)

brute force, data structures, math, number theory

Rearrange Brackets

brute force, dp, greedy, sortings, strings

Between

constructive algorithms, dfs and similar, graphs, greedy

Chain Chips

data structures, dp, matrices

Vlad and the Nice Paths (hard version)

binary search, combinatorics, data structures, dp, math, two pointers

Vlad and the Nice Paths (easy version)

combinatorics, dp, math

Is It Flower?

dfs and similar, graphs, implementation

Monsters

brute force, data structures, dfs and similar, dsu, graphs, greedy

Minibuses on Venus (easy version)

combinatorics, divide and conquer, dp

Petya, Petya, Petr, and Palindromes

binary search, brute force, data structures, two pointers

Tree Master

brute force, data structures, dfs and similar, trees

There Should Be a Lot of Maximums

brute force, data structures, dfs and similar, dp, trees, two pointers

The way home

binary search, data structures, dp, graphs, greedy, shortest paths, sortings

Symmetree

dfs and similar, hashing, implementation, trees

City Union

constructive algorithms, dfs and similar, dsu, geometry, greedy, implementation, math

Hot Start Up (hard version)

data structures, dp

Multitest Generator

brute force, dp

Li Hua and Array

brute force, data structures, dsu, math, number theory, two pointers

Explosions?

binary search, data structures, dp, greedy, math

Tokens on Graph

constructive algorithms, dfs and similar, graphs, shortest paths

Timofey and Black-White Tree

brute force, dfs and similar, divide and conquer, graphs, greedy, math, shortest paths, trees

Serval and Shift-Shift-Shift

bitmasks, brute force, constructive algorithms, implementation

Sum Over Zero

data structures, dfs and similar, dp

The Harmonization of XOR

bitmasks, constructive algorithms, greedy, math

Monsters (hard version)

data structures, greedy

Game of the Year

brute force, data structures, math, number theory

Rectangle Shrinking

binary search, brute force, data structures, greedy, implementation, two pointers

Three Chairs

bitmasks, brute force, combinatorics, data structures, dp, number theory, sortings

Flexible String Revisit

combinatorics, dp, math, probabilities

Edge Reverse

binary search, dfs and similar, graphs, trees

Another Wine Tasting Event

combinatorics, constructive algorithms, math, strings

Vittorio Plays with LEGO Bricks

dp, geometry

The Human Equation

greedy, implementation

BinCoin

binary search, divide and conquer, hashing, implementation, probabilities, trees

Gaining Rating

binary search, greedy, implementation, math, sortings, two pointers

Hossam and (sub-)palindromic tree

brute force, data structures, dfs and similar, dp, strings, trees

Игра в Девятку III

*special problem, brute force

Игра в Девятку II

*special problem, brute force

Partial Sorting

combinatorics, math, number theory

Count Binary Strings

data structures, dp

Decomposition

binary search, brute force, data structures, divide and conquer, dp, two pointers

Hospital Queue

binary search, graphs, greedy, implementation

Chemistry Lab

dp, geometry, probabilities

Node Pairs

dp, graphs, math, number theory

Valid Bitonic Permutations

combinatorics, dp, implementation, math, number theory

GCD Queries

constructive algorithms, interactive, number theory

Carry Bit

combinatorics, math

Yet Another Array Counting Problem

binary search, data structures, divide and conquer, dp, flows, math, trees

ConstructOR

bitmasks, chinese remainder theorem, combinatorics, constructive algorithms, math, number theory

Intersection and Union

data structures, dp, matrices, probabilities

Kirill and Company

bitmasks, brute force, dfs and similar, dp, flows, graphs, shortest paths

Balance Addicts

combinatorics, dp, math, two pointers

Ela and the Wiring Wizard

brute force, dp, graphs, greedy, implementation, shortest paths

Equal Binary Subsequences

constructive algorithms, geometry, greedy, implementation, strings

Rectangular Congruence

constructive algorithms, number theory

Sheikh (Hard Version)

binary search, bitmasks, brute force, greedy, implementation, two pointers

Prefixes and Suffixes

constructive algorithms, strings, two pointers

Cut Substrings

combinatorics, dp, hashing, strings, two pointers

Red-Black Pepper

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

Field Photography

bitmasks, data structures, sortings

Prefix Function Queries

dfs and similar, dp, hashing, string suffix structures, strings, trees

Madoka and The Best University

math, number theory

LCM Sum (easy version)

binary search, brute force, combinatorics, math, number theory, two pointers

Rain

binary search, brute force, data structures, geometry, greedy, implementation, math

Qpwoeirut and Vertices

binary search, data structures, dfs and similar, divide and conquer, dsu, greedy, trees

Mark and Professor Koro

binary search, bitmasks, brute force, combinatorics, data structures, greedy

Count Seconds

brute force, constructive algorithms, dp, graphs, implementation, math

Almost Triple Deletions

data structures, dp, greedy

PermutationForces II

brute force, combinatorics, greedy, sortings, trees, two pointers

Tree Queries (Hard Version)

constructive algorithms, dfs and similar, dp, greedy, trees

Tree Queries (Easy Version)

brute force, constructive algorithms, dfs and similar, dp, greedy, trees

Keshi in Search of AmShZ

graphs, greedy, shortest paths

Number of Groups

data structures, dfs and similar, dsu, graphs, greedy, sortings

MEX vs DIFF

binary search, brute force, constructive algorithms, data structures, greedy, two pointers

Unique Occurrences

data structures, dfs and similar, divide and conquer, dp, dsu, trees

Sorting Pancakes

dp

notepad.exe

binary search, constructive algorithms, greedy, interactive

Preorder

combinatorics, divide and conquer, dp, dsu, hashing, sortings, trees

Hemose on the Tree

bitmasks, constructive algorithms, dfs and similar, trees

Optimal Partition

data structures, dp

Job Lookup

constructive algorithms, dp, shortest paths, trees

Interactive Treasure Hunt

brute force, constructive algorithms, geometry, interactive, math

Fancy Stack

combinatorics, dp, implementation

Promising String (hard version)

data structures, implementation, math, strings

AND-MEX Walk

bitmasks, brute force, constructive algorithms, dfs and similar, dsu, graphs

388535 (Hard Version)

bitmasks, brute force, data structures, math

Star MST

combinatorics, dp, graph matchings, math

Equal Tree Sums

constructive algorithms, dfs and similar, math, trees

Arithmetic Operations

brute force, data structures, graphs, math

Potion Brewing Class

dfs and similar, math, number theory, trees

Counting Shortcuts

data structures, dfs and similar, dp, graphs, shortest paths

Vitaly and Advanced Useless Algorithms

dp, greedy, implementation

Power Board

brute force, dp, math, number theory

Anonymity Is Important

binary search, brute force, data structures, dsu, greedy, sortings

Best Pair

binary search, brute force, implementation

Cars

2-sat, constructive algorithms, dfs and similar, dsu, graphs, greedy, sortings

Paint the Middle

dp, greedy, sortings, two pointers

Game on Sum (Easy Version)

combinatorics, dp, games, math