Chessboard

bitmasks, brute force, implementation

Santa's Gift

data structures, trees

Bandit Blues

combinatorics, dp, fft, math

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

Subsequence Counting

bitmasks, constructive algorithms, greedy, implementation

Minimize the error

data structures, greedy, sortings

Mahmoud and Ehab and yet another xor task

bitmasks, dp, math, matrices

Mahmoud and Ehab and the xor-MST

bitmasks, dp, graphs, implementation, math

Mahmoud and Ehab and another array construction task

constructive algorithms, greedy, math, number theory

Mahmoud and Ehab and the wrong algorithm

constructive algorithms, trees

Lightsabers (hard)

fft

Lightsabers (medium)

binary search, two pointers

Lightsabers (easy)

implementation

Guard Duty (hard)

geometry

Guard Duty (medium)

binary search, dp, greedy, sortings

Guard Duty (easy)

brute force, geometry, greedy, math

Hyperspace Jump (hard)

Hyperspace Jump (easy)

expression parsing, math

Encryption (hard)

data structures, dp

Encryption (medium)

dp

Maximum Control (medium)

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

Death Stars (hard)

Death Stars (medium)

hashing, strings

Death Stars (easy)

implementation

Heaps

dp, trees

Icicles

Scissors

brute force, strings

Sad powers

binary search, math, number theory

Not simply beatiful strings

implementation

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

Fight Against Traffic

dfs and similar, graphs, shortest paths

Matrix Walk

implementation

String Typing

implementation, strings

Puzzling Language

constructive algorithms

2 + 2 != 4

Cheese Board

I'm Feeling Lucky!

probabilities

Ravioli Sort

implementation

A Map of the Cat

*special problem, brute force, interactive

Astronomy

geometry, probabilities

Binary Cards

brute force

Curfew

binary search, brute force, greedy, sortings

Data Center Maintenance

dfs and similar, graphs

A Leapfrog in the Array

constructive algorithms, math

Zebras

greedy

Almost Increasing Array

data structures, dp

Fibonacci String Subsequences

combinatorics, dp, matrices

Largest Beautiful Number

greedy, implementation

Timetable

dp

Machine Learning

brute force, data structures

Cashback

data structures, dp, greedy, math

Alena And The Heater

binary search, implementation

Phone Numbers

constructive algorithms, implementation, strings

Our Tanya is Crying Out Loud

dp, greedy

Cutlet

data structures, dp

Maximize!

binary search, greedy, ternary search, two pointers

Love Rescue

dfs and similar, dsu, graphs, greedy, strings

Convenient For Everybody

binary search, two pointers

Shortest Path Queries

bitmasks, data structures, dsu, graphs

Erasing Substrings

bitmasks, dp, greedy

Max History

combinatorics, math

Buy a Ticket

data structures, graphs, shortest paths

Constructing Tests

binary search, brute force, constructive algorithms

Vile Grasshoppers

brute force, math, number theory

Iqea

data structures, dfs and similar, divide and conquer, dsu, shortest paths, trees

World of Tank

dp, greedy

Lock Puzzle

constructive algorithms, implementation, strings

Sleepy Game

dfs and similar, dp, games, graphs

Save Energy!

binary search, implementation, math

Fafa and Array

data structures, greedy

Fafa and Ancient Mathematics

dfs and similar, dp, trees

Fafa and Ancient Alphabet

math, probabilities

Fifa and Fafa

geometry

A Compatible Pair

brute force, games

A Preponderant Reunion

constructive algorithms, dp

A Creative Cutout

brute force, combinatorics, math

A Colourful Prospect

geometry, graphs

A Determined Cleanup

math

A Twisty Movement

dp

Palindrome Partition

dp, string suffix structures, strings

Escape Through Leaf

data structures, dp, geometry

Team Work

combinatorics, dp, math

Tree

binary search, dp, trees

Permutation Cycle

brute force, constructive algorithms

Laboratory Work

implementation, math

Coins Exhibition

data structures, dp, math

Game with Tokens

data structures, games, implementation

Teodor is not a liar!

data structures, dp

Game with String

implementation, probabilities, strings

Peculiar apple-tree

dfs and similar, graphs, trees

Пограничные врата

Красивая команда

*special problem, combinatorics, math

Прокат велосипедов

*special problem, greedy, implementation

Autocompletion

*special problem, strings, trees