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

Closest Cities

greedy, implementation, math

Forming Triangles

combinatorics, constructive algorithms, math, sortings

Tricky Template

constructive algorithms, implementation, strings

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

Very Different Array

data structures, greedy, sortings, two pointers

Sending Messages

greedy, math

Arranging Cats

greedy, implementation

Square

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

Summation Game

games, greedy, math, sortings

Satisfying Constraints

brute force, greedy, math

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

Plus-Minus Split

greedy

Wallet Exchange

games, math

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

Minimize Inversions

constructive algorithms, data structures, greedy, implementation, sortings

Brick Wall

constructive algorithms, 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

Erase First or Second Letter

brute force, combinatorics, data structures, dp, strings

Least Product

constructive algorithms, 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

Training Before the Olympiad

constructive algorithms, games, greedy, implementation, math

Two Divisors

constructive algorithms, math, number theory

2023

constructive algorithms, implementation, math, number theory

Bicycles

graphs, greedy, implementation, shortest paths, sortings

Greetings

data structures, divide and conquer, sortings

Romantic Glasses

data structures, greedy, math

Unnatural Language Processing

greedy, implementation, strings

Can I Square?

binary search, implementation

Not Quite Latin Square

bitmasks, brute force, implementation

Odd One Out

bitmasks, implementation

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

Three Activities

brute force, dp, greedy, implementation, sortings

Quests

greedy, math

Preparing for the Contest

constructive algorithms, math

Problemsolving Log

implementation, strings

Palindromic Problem

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

Matrix Problem

flows, graphs

Array Collapse

data structures, divide and conquer, dp, trees

Game with Multiset

binary search, bitmasks, brute force, greedy

Swap and Delete

strings

Rating Increase

implementation

LOL Lovers

strings

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

Remove and Add

*special problem, greedy

Poisonous Swamp

*special problem, *special problem, implementation, implementation

Security Guard

*special problem, greedy

Username

*special problem, implementation

Short Permutation Problem

combinatorics, dp, fft, math

Parallel Swaps Sort

constructive algorithms, data structures

Pumping Lemma

hashing, strings

Small Permutation Problem (Hard Version)

combinatorics, dp, math

Small Permutation Problem (Easy Version)

brute force, combinatorics, dp, math