Equal Reversal

constructive algorithms, graphs, implementation, math

Too Many Constraints

2-sat, constructive algorithms, graphs, implementation

Decinc Dividing

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

Cute number

binary search, brute force, data structures, dsu, implementation, math

Permutation Weight (Easy Version)

constructive algorithms, dfs and similar, dsu

Euclid Guess

constructive algorithms, flows, graph matchings, math, number theory

Tokitsukaze and Beautiful Subsegments

data structures

PermutationForces

data structures, greedy

Checker for Array Shuffling

constructive algorithms, dfs and similar, graphs

Centroid Probabilities

combinatorics, dp, fft, math

Edge Elimination

constructive algorithms, dfs and similar, dp, trees

Tree and Permutation Game

dfs and similar, games, graphs, trees

Snowy Mountain

data structures, dfs and similar, graphs, greedy, shortest paths, trees

Minimal String Xoration

bitmasks, data structures, divide and conquer, greedy, hashing, sortings, strings

Tower Defense

binary search, brute force, data structures

Serious Business

data structures, divide and conquer, dp, implementation, shortest paths

Playing Around the Table

constructive algorithms, greedy, implementation

Basis

combinatorics, fft, math, number theory

Birthday

constructive algorithms, greedy, math

Closest Pair

data structures, greedy

Perfect Matching

data structures, divide and conquer, interactive, trees

Expected Components

combinatorics, math, number theory, probabilities

A Random Code Problem

combinatorics, dp, math, number theory, probabilities

Cats on the Upgrade (hard version)

binary search, data structures, dfs and similar, graphs, trees

Quadratic Set

constructive algorithms, hashing, math, number theory

Bipartite Array

dp, greedy

Keep XOR Low

bitmasks, combinatorics, data structures, divide and conquer, dp, math

Tricolor Triangles

brute force, graphs, math, matrices

Reindeer Games

binary search, constructive algorithms, data structures, divide and conquer, flows, graphs, shortest paths

LEGOndary Grandmaster

combinatorics, dp, math

Armor and Weapons

brute force, dp, greedy, shortest paths

Mashtali: a Space Oddysey

constructive algorithms, dfs and similar, graphs

A Stroll Around the Matrix

data structures, greedy, math

Interesting Sections

data structures, divide and conquer, meet-in-the-middle, two pointers

The Cells on the Paper

binary search, implementation, sortings

Tree Queries

brute force, dp, trees

PalindORme

combinatorics, dp

Artistic Partition

divide and conquer, dp, number theory

Phys Ed Online

data structures, dp, greedy

Alice and Recoloring 2

constructive algorithms, flows, graph matchings, greedy

Omkar and Time Travel

data structures, math

Subsequence

brute force, divide and conquer, dp, greedy, trees

Kingdom of Islands

brute force, graphs, implementation

Framing Pictures

geometry

Building Forest Trails

data structures, dsu

Anti-Tetris

constructive algorithms, graphs, shortest paths

Finding Expected Value

math

Cyclic Sum

data structures, fft, number theory

Polygon

binary search, dp, geometry

Bridge Club

flows, graph matchings, graphs, greedy

Two Railroads

*special problem

Laser Beams

*special problem, geometry, probabilities

Palindromic Hamiltonian Path

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

Tubular Bells

interactive, math, number theory, probabilities

Down Below

binary search, dfs and similar, graphs, greedy, meet-in-the-middle, shortest paths

Assiut Chess

brute force, constructive algorithms, interactive

XOR and Distance

bitmasks, divide and conquer, trees

A Serious Referee

bitmasks, brute force, dfs and similar, sortings

AquaMoon and Wrong Coordinate

constructive algorithms, interactive, math

AquaMoon and Permutations

2-sat, brute force, combinatorics, constructive algorithms, graph matchings, graphs

Converging Array (Hard Version)

dp, math

String Distance

binary search, brute force, data structures, hashing, implementation, strings

Falling Sand (Hard Version)

dfs and similar, dp, graphs, greedy

Mashtali and Hagh Trees

combinatorics, dp, trees

Median Queries

constructive algorithms, interactive, probabilities

Goblins And Gnomes

brute force, dp, flows, graph matchings

Fiber Shape

Cactus Not Enough

dfs and similar, graph matchings, graphs

Swap Pass

constructive algorithms, geometry, sortings

Tiles for Bathroom

data structures, sortings, two pointers

Delete The Edges

brute force, constructive algorithms, dfs and similar, graphs, implementation

Switch and Flip

constructive algorithms, graphs, math

Build From Suffixes

*special problem, combinatorics, data structures

Ones

dp, greedy, shortest paths

Odd Mineral Resource

binary search, bitmasks, brute force, data structures, probabilities, trees

Nezzar and Hidden Permutations

constructive algorithms, dfs and similar, graphs

Lanterns

binary search, data structures, dp

1 2 3 4 ...

dp, math, matrices

Tiles

combinatorics, dp, fft, math

Bakery

data structures, dsu

Forbidden Value

data structures, dp

String and Operations

dp, greedy

Divide Powers

constructive algorithms, greedy

Multithreading (Easy Version)

combinatorics, fft, math

Frequency Problem (Hard Version)

data structures, greedy, two pointers

Rectangular Polyline

constructive algorithms, dp, geometry

Black, White and Grey Tree

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

Sum

data structures, divide and conquer, dp, greedy

Olha and Igor

interactive, probabilities, trees

Sum Over Subsets

combinatorics, math, number theory

Cyclic Shifts

*special problem, strings

Lucky Numbers (Hard Version)

dp, greedy

Lucky Numbers (Easy Version)

dp, greedy

Impressive Harvesting of The Orchard

data structures

Milutin's Plums

interactive

Lookup Tables

bitmasks

Rain of Fire

binary search, data structures, dfs and similar, dsu, graphs, implementation

Equal Product

data structures, math, number theory, two pointers

Cakes for Clones

dp

Roads and Ramen

data structures, trees