Pencils and Boxes

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

Sand Fortress

binary search, constructive algorithms, math

Liebig's Barrels

greedy

Switches and Lamps

implementation

Chess Placing

implementation

Minesweeper

implementation

Game

sortings

NN country

binary search, data structures, trees

Arkady and Rectangles

data structures

Elevator

dp, graphs, shortest paths

XOR-pyramid

dp

Finite or not?

implementation, math

The Meeting Place Cannot Be Changed

dfs and similar, graphs

Billiard

geometry, number theory

Shark

brute force, data structures, dsu, trees

Cut 'em all!

dfs and similar, dp, graphs, greedy, trees

Bus of Characters

data structures, greedy, implementation

Row

brute force, constructive algorithms

K Paths

combinatorics, data structures, dp, fft, math

Magic multisets

data structures

Round Marriage

binary search, graph matchings, greedy

Addition on Segments

bitmasks, data structures, divide and conquer, dp

Bookshelves

bitmasks, dp, greedy

Useful Decomposition

implementation, trees

Businessmen Problems

sortings

Antipalindrome

brute force, implementation, strings

Cactus to Tree

dp, graphs, trees

The Number Games

data structures, greedy, trees

Perfect Groups

dp, math, number theory

Posterized

games, greedy

Marlin

constructive algorithms

Links and Pearls

implementation, math

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

Kuro and Walking Route

dfs and similar, trees

Treasure Hunt

greedy

Pizza, Pizza, Pizza!!!

math

Petya's Exams

greedy, implementation, sortings

Mentors

binary search, data structures, implementation

Bus Video System

combinatorics, math

Almost Arithmetic Progression

brute force, implementation, math

Letters

binary search, implementation, two pointers

File Name

greedy, strings

Remove Duplicates

implementation

Consecutive Subsequence

dp

Cyclic Components

dfs and similar, dsu, graphs

Divide by three, multiply by two

dfs and similar, math, sortings

Less or Equal

sortings

Two-gram

implementation, strings

Wrong Subtraction

implementation

Minimal k-covering

flows, graphs

Well played!

greedy, sortings

Degree Set

constructive algorithms, graphs, implementation

Nested Segments

greedy, implementation, sortings

Lara Croft and the New Game

implementation, math

Minimum Binary Number

implementation

Hag's Khashba

geometry

Ghosts

geometry, math

Valhalla Siege

binary search

Mancala

brute force, implementation

Aramic script

implementation, strings

Watering System

math, sortings

Mind the Gap

implementation

Short Code

data structures, dp, greedy, strings, trees

Single-use Stones

binary search, flows, greedy, two pointers

Greedy Arkady

math

Battleship

implementation

Paper Airplanes

math

Messages

math

Splits

math

Circles of Waiting

math

Frequency of String

hashing, string suffix structures, strings

Cutting Rectangle

brute force, math, number theory

Destruction of a Tree

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

Alternating Sum

math, number theory

Visible Black Areas

data structures, dsu, geometry, trees

Simple Cycles Edges

dfs and similar, graphs, trees

Byteland, Berland and Disputed Cities

constructive algorithms, greedy

Merge Equals

data structures, implementation

Make a Square

brute force, implementation, math

Students in Railway Carriage

constructive algorithms, greedy, implementation

Equator

implementation

Partitions

combinatorics, math, number theory

k-substrings

binary search, hashing, string suffix structures

Tufurama

data structures

Pair Of Lines

geometry

Chessboard

bitmasks, brute force, implementation

Lecture Sleep

data structures, dp, implementation, two pointers

Tetris

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

Check the string

implementation

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