Railway Construction

brute force, constructive algorithms, data structures, graphs, shortest paths

Subsequence

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

Train Maintenance

brute force, data structures, implementation

Mathematics Curriculum

brute force, combinatorics, dp, trees

Portal

brute force, data structures, dp, greedy, implementation

Minimal Coverage

dp

Array Stabilization (AND version)

brute force, graphs, math, number theory, shortest paths

Array Optimization by Deque

data structures, greedy

The Mind

constructive algorithms, interactive, probabilities

Labyrinth

binary search, dsu, greedy

Kingdom of Islands

brute force, graphs, implementation

Just Kingdom

brute force, data structures, dfs and similar

Interactive Rays

geometry, interactive

Higher Order Functions

implementation, strings

Game of Chance

math, probabilities

Framing Pictures

geometry

Dragon Curve

Cactus Lady and her Cing

Building Forest Trails

data structures, dsu

Anti-Tetris

constructive algorithms, graphs, shortest paths

Managing Telephone Poles

data structures, geometry

Longest Array Deconstruction

data structures, divide and conquer, dp, sortings

Knitting Batik

implementation, math

Illusions of the Desert

data structures, trees

Holiday Wall Ornaments

dp, strings

GCD Festival

math, number theory

Finding Expected Value

math

Eye-Pleasing City Park Tour

data structures, trees

Divisible by Twenty-Five

brute force, dfs and similar, dp

Cyclic Sum

data structures, fft, number theory

Building an Amusement Park

binary search, geometry

Occurrences

combinatorics, dfs and similar, dp, dsu, fft, graphs

Coloring

combinatorics, constructive algorithms, implementation, math

The Strongest Build

binary search, brute force, data structures, dfs and similar, graphs, greedy, hashing, implementation

Stations

data structures

Polygon

binary search, dp, geometry

Bridge Club

flows, graph matchings, graphs, greedy

Paint

dp, greedy

Xor of 3

brute force, constructive algorithms, greedy, two pointers

Book

binary search, brute force, data structures, dp, graphs, implementation, sortings

Two Railroads

*special problem

Physical Examination

*special problem, binary search, data structures

Laser Beams

*special problem, geometry, probabilities

A Battle Against a Dragon

*special problem, data structures, dp

Kotlinforces

*special problem, constructive algorithms, dp

Fix the String

*special problem, bitmasks, dp, greedy

Sweepstake

*special problem, brute force, constructive algorithms, implementation, math

Rhyme

*special problem, implementation

Palindromic Hamiltonian Path

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

Playoff Restoration

bitmasks, brute force, hashing, implementation, meet-in-the-middle

Inconvenient Pairs

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

One-Four Overload

2-sat, constructive algorithms, dfs and similar, dsu, graphs, implementation

Non-Decreasing Dilemma

data structures, divide and conquer, math

Expression Evaluation Error

constructive algorithms, greedy, implementation, math

Carrying Conundrum

bitmasks, combinatorics, dp, math

Xor-quiz

constructive algorithms, dp, interactive, math, number theory

Four Vertices

constructive algorithms, data structures, graphs, greedy, implementation, shortest paths

Points Movement

data structures, dp, greedy, implementation, sortings

Buds Re-hanging

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

Seating Arrangements (hard version)

data structures, greedy, implementation, sortings, two pointers

Tubular Bells

interactive, math, number theory, probabilities

Rescue Niwen!

dp, greedy, string suffix structures, strings

Two Hundred Twenty One (hard version)

data structures, math

Two Hundred Twenty One (easy version)

data structures, dp, math

Up the Strip (simplified version)

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

Nearest Beautiful Number (hard version)

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

Nearest Beautiful Number (easy version)

binary search, bitmasks, brute force, constructive algorithms, dfs and similar, greedy

Polycarp and String Transformation

binary search, implementation, sortings, strings

Mocha and Stars

combinatorics, dp, fft, math, number theory

Mocha and Diana (Hard Version)

brute force, constructive algorithms, dfs and similar, dsu, graphs, greedy, trees, two pointers

Strange Sort

data structures, sortings

Down Below

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

Top-Notch Insertions

combinatorics, data structures

Bottom-Tier Reversals

constructive algorithms, greedy

Up the Strip

brute force, dp, math, number theory, two pointers

Assiut Chess

brute force, constructive algorithms, interactive

Ezzat and Grid

data structures, dp, greedy

Moamen and XOR

bitmasks, combinatorics, dp, math, matrices

DIY Tree

graphs, greedy, math, probabilities

Gates to Another World

bitmasks, data structures, dsu, two pointers

Sports Betting

bitmasks, combinatorics, dp, graphs, math, probabilities

Equilibrium

data structures, dp, greedy

Take a Guess

bitmasks, constructive algorithms, interactive, math

Compressed Bracket Sequence

brute force, implementation

Good Graph

data structures, dsu, graphs, trees

Boring Segments

data structures, sortings, trees, two pointers

Say No to Palindromes

brute force, constructive algorithms, dp, strings

You

dfs and similar, dp, math, number theory

Diane

constructive algorithms, greedy, strings

Mikasa

binary search, bitmasks, greedy, implementation

Cobb

bitmasks, brute force, greedy, math

Stairs

combinatorics, divide and conquer, dp, fft, math

XOR and Distance

bitmasks, divide and conquer, trees

Common Divisor Graph

brute force, constructive algorithms, dsu, graphs, hashing, math, number theory

Pairwise Modulo

data structures, math

Permutation Shift

brute force, combinatorics, constructive algorithms, dfs and similar, dsu, graphs, math

Organizing a Music Festival

dfs and similar, math

Guess the Perimeter

binary search, interactive, number theory

A Serious Referee

bitmasks, brute force, dfs and similar, sortings

Telepanting

binary search, data structures, dp, sortings