Feed Cats

data structures, dp, sortings

Final Countdown

implementation, math, number theory

Card Game

greedy, implementation

LR-remainders

brute force, data structures, implementation, math, two pointers

One-Dimensional Puzzle

combinatorics, math, number theory

Chat Screenshots

combinatorics, dfs and similar, graphs

Anna and the Valentine's Day Gift

games, greedy, math, sortings

Counting Is Fun

combinatorics

Interactive Mex Tree

constructive algorithms, dfs and similar, interactive, trees

Prefix Max Set Counting

data structures, dp, trees

Maximize the Difference

bitmasks, brute force, dfs and similar

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

Lexicographically Largest

binary search, constructive algorithms, data structures, greedy, sortings

Sasha and the Wedding Binary Search Tree

brute force, combinatorics, data structures, dfs and similar, math, trees

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

Sasha and the Casino

binary search, brute force, constructive algorithms, games, greedy, math

Digital Patterns

combinatorics, data structures, implementation, math

Modular Sequence

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

Lonely Mountain Dungeons

brute force, data structures, greedy, math, ternary search

Physical Education Lesson

brute force, math, number theory

Paint Charges

data structures, dp, greedy, math

Microcycle

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

Klever Permutation

constructive algorithms, math, two pointers

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

Vlad and an Odd Ordering

binary search, bitmasks, data structures, dp, implementation, math, number theory

Good Trip

combinatorics, dp, math, probabilities

Anti-Proxy Attendance

constructive algorithms, dp, interactive, ternary search

Paper Cutting Again

combinatorics, probabilities

Balanced Subsequences

combinatorics, dp, math

Fractal Origami

geometry, math, matrices

Space Harbour

data structures, implementation, math, sortings

Did We Get Everything Covered?

constructive algorithms, dp, greedy, shortest paths, strings

Shrink-Reverse

binary search, brute force, greedy, hashing, implementation, string suffix structures, strings

Count Paths

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

Slimes

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

Find B

constructive algorithms, greedy

Replace on Segment

dp, graph matchings

Increasing Subsequences

bitmasks, constructive algorithms, divide and conquer, greedy, math

Berserk Monsters

brute force, data structures, dsu, implementation, math

Mischievous Shooter

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

Sum of Progression

brute force, data structures, dp, implementation, math

Eat the Chip

brute force, games, greedy, math

Smooth Sailing (Hard Version)

binary search, data structures, dsu, geometry, graphs, trees

Smooth Sailing (Easy Version)

binary search, brute force, data structures, dfs and similar, dsu, graphs, shortest paths

Counting Binary Strings

combinatorics, dp, math

Array Repetition

binary search, brute force, dsu, implementation, math

Partitioning the Array

brute force, math, number theory

Tree Diameter

interactive, trees

Tree LGM

constructive algorithms, divide and conquer, games, trees

Wine Factory (Hard Version)

data structures, dp, flows, greedy, matrices

Wine Factory (Easy Version)

data structures, greedy

Counting Prefixes

combinatorics, constructive algorithms, dp, implementation, math

01 Tree

constructive algorithms, data structures, dsu, greedy, sortings, trees

Grouping Increases

data structures, dp, greedy

Permutation of Given

constructive algorithms, math

Caterpillar on a Tree

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

ace5 and Task Order

constructive algorithms, divide and conquer, implementation, interactive, probabilities, sortings

Blocking Elements

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

XOR-distance

bitmasks, greedy, implementation, math

Construct Tree

bitmasks, constructive algorithms, dp, trees

Construct Matrix

constructive algorithms, math

Yet Another Inversions Problem

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

Watering an Array

brute force, greedy, implementation, math

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

Group Division

constructive algorithms, dfs and similar, graphs, greedy

Happy Life in University

data structures, dfs and similar, greedy, trees

Mathematical Problem

brute force, constructive algorithms, geometry, math

Bicycles

graphs, greedy, implementation, shortest paths, sortings

Greetings

data structures, divide and conquer, sortings

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

Game with Marbles (Hard Version)

games, greedy, sortings

Game with Marbles (Easy Version)

brute force, games, greedy, sortings

Palindromic Problem

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

Matrix Problem

flows, graphs

Array Collapse

data structures, divide and conquer, dp, trees

Kim's Quest

bitmasks, combinatorics, dp

Joy of Pokémon Observation

Innovative Washing Machine

geometry, math, two pointers

Hypercatapult Commute

graphs

Great City Saint Petersburg

data structures

Fugitive Frenzy

math, probabilities

Evaluate It and Back Again

constructive algorithms, implementation, math

Divisibility Test

math

Cactus Transformation

constructive algorithms

Blueprint for Seating

combinatorics, divide and conquer, math

Accumulator Apex

data structures, implementation, sortings

Two Colors

*special problem

Inverse Problem

*special problem, combinatorics, dp

Sum of Digits of Sums

*special problem, binary search, data structures

Pool Records

*special problem, greedy

Build Railway Stations

*special problem, greedy, trees

Maximum Sum Subarrays

*special problem, dp