Isomorphic Strings

hashing, strings

Pencils and Boxes

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

Sand Fortress

binary search, constructive algorithms, math

Elevator

dp, graphs, shortest paths

Magic multisets

data structures

Round Marriage

binary search, graph matchings, greedy

Addition on Segments

bitmasks, data structures, divide and conquer, dp

The Number Games

data structures, greedy, trees

Perfect Groups

dp, math, number theory

Kuro and Topological Parity

dp

Kuro and GCD and XOR and SUM

binary search, bitmasks, brute force, data structures, dp, dsu, greedy, math, number theory, strings, trees

Minimal k-covering

flows, graphs

Well played!

greedy, sortings

Degree Set

constructive algorithms, graphs, implementation

Ghosts

geometry, math

Short Code

data structures, dp, greedy, strings, trees

Greedy Arkady

math

Frequency of String

hashing, string suffix structures, strings

Destruction of a Tree

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

Simple Cycles Edges

dfs and similar, graphs, trees

Byteland, Berland and Disputed Cities

constructive algorithms, greedy

Pair Of Lines

geometry

Pathwalks

data structures, dp, graphs

Alternating Tree

combinatorics, dfs and similar, divide and conquer, dp, probabilities, trees

Full Binary Tree Queries

brute force, implementation, trees

Mahmoud and Ehab and yet another xor task

bitmasks, dp, math, matrices

Guard Duty (medium)

binary search, dp, greedy, sortings

Encryption (hard)

data structures, dp

Encryption (medium)

dp

Maximum Control (medium)

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

Death Stars (medium)

hashing, strings

Sad powers

binary search, math, number theory

Yet Another String Matching Problem

fft, math

Path Counting

combinatorics, dp

Castle Defense

binary search, data structures, greedy, two pointers

Runner's Problem

dp, matrices, sortings

Water Taps

binary search, greedy, sortings

Puzzling Language

constructive algorithms

2 + 2 != 4

Cheese Board

Curfew

binary search, brute force, greedy, sortings

Almost Increasing Array

data structures, dp

Fibonacci String Subsequences

combinatorics, dp, matrices

Largest Beautiful Number

greedy, implementation

Cashback

data structures, dp, greedy, math

Cutlet

data structures, dp

Max History

combinatorics, math

Buy a Ticket

data structures, graphs, shortest paths

Lock Puzzle

constructive algorithms, implementation, strings

Sleepy Game

dfs and similar, dp, games, graphs

Fafa and Ancient Mathematics

dfs and similar, dp, trees

A Determined Cleanup

math

Team Work

combinatorics, dp, math

Tree

binary search, dp, trees

Game with Tokens

data structures, games, implementation

Пограничные врата

Segments

data structures

Endless Roses Most Beautiful

Mobile Communications

Big Secret

constructive algorithms, math

Contact ATC

Picking Strings

constructive algorithms, implementation, strings

Divisibility

constructive algorithms, dp, greedy, number theory

Birds

dp

List Of Integers

binary search, bitmasks, brute force, combinatorics, math, number theory

SUM and REPLACE

brute force, data structures, dsu, number theory

Connected Components?

data structures, dfs and similar, dsu, graphs

Tanks

dp, greedy, implementation

Congruence Equation

chinese remainder theorem, math, number theory

Jamie and Tree

data structures, trees

Jamie and To-do List

data structures, interactive, trees

Jamie and Binary Sequence (changed after round)

bitmasks, greedy, math

Coprime Arrays

math, number theory

Imbalance Value of a Tree

data structures, dsu, graphs, trees

Physical Education Lessons

data structures, implementation, sortings

Almost Acyclic Graph

dfs and similar, graphs

Palindromes in a Tree

bitmasks, data structures, divide and conquer, trees

Logical Expression

bitmasks, dp, shortest paths

Prime Gift

binary search, dfs and similar, math, meet-in-the-middle, number theory, two pointers

Fishes

data structures, graphs, greedy, probabilities, shortest paths

Perun, Ult!

brute force, greedy, sortings

Mass Change Queries

data structures

Tree Destruction

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

Stack Sorting

constructive algorithms, data structures, greedy, implementation

AND-permutations

constructive algorithms

Colorful Points

data structures, greedy, implementation

New Year and Rainbow Roads

graphs, greedy, implementation

New Year and Entity Enumeration

bitmasks, combinatorics, dp, math

New Year and Arbitrary Arrangement

dp, math, probabilities

Party

bitmasks, brute force, dp, graphs

Seating of Students

brute force, constructive algorithms, math

Clear The Matrix

bitmasks, dp

Swapping Characters

brute force, hashing, implementation, strings

Almost Difference

data structures, math

Bipartite Segments

binary search, data structures, dfs and similar, dsu, graphs, two pointers

GCD of Polynomials

constructive algorithms, math

Maximum Questions

data structures, dp, strings

Unusual Sequences

bitmasks, combinatorics, dp, math, number theory

Letters Removing

data structures, strings

Segments Removal

data structures, dsu, flows, implementation, two pointers