Ela Takes Dancing Class

binary search, data structures

Ela and Prime GCD

constructive algorithms, math, number theory

Ela Goes Hiking

combinatorics, dp, math, probabilities

Ela and the Wiring Wizard

brute force, dp, graphs, greedy, implementation, shortest paths

Swap and Take

dp, greedy

Equal Binary Subsequences

constructive algorithms, geometry, greedy, implementation, strings

Good Subarrays (Hard Version)

binary search, data structures, dp, two pointers

Pebbles and Beads

data structures, geometry

House Planning

constructive algorithms, data structures, graph matchings, greedy

Meta-set

brute force, combinatorics, data structures, hashing, math

Zeros and Ones

bitmasks, divide and conquer, dp, math

Rectangular Congruence

constructive algorithms, number theory

Slime Escape

data structures, dp, greedy, two pointers

Conveyor

constructive algorithms, dp, math

Zero-One (Hard Version)

dp, greedy

Location

data structures, dp, math, number theory

Balance (Hard version)

brute force, data structures, number theory

Sheikh (Hard Version)

binary search, bitmasks, brute force, greedy, implementation, two pointers

Sheikh (Easy version)

binary search, bitmasks, greedy, two pointers

Function Sum

brute force, combinatorics, dp, fft, math

Graph Cost

dp, greedy, math, number theory

Valiant's New Map

binary search, brute force, data structures, dp, two pointers

Even Subarrays

bitmasks, brute force, hashing, math, number theory

Almost Sorted

bitmasks, data structures, dp

Maximums and Minimums

combinatorics, data structures, divide and conquer, number theory

Prefixes and Suffixes

constructive algorithms, strings, two pointers

Meeting on the Line

binary search, geometry, greedy, implementation, math, ternary search

Cut Substrings

combinatorics, dp, hashing, strings, two pointers

Kirei and the Linear Function

hashing, math

Guess the Cycle Size

interactive, probabilities

Illumination

binary search, bitmasks, brute force, combinatorics, dp, math, two pointers

Fishermen

flows, graph matchings, greedy

Red-Black Pepper

brute force, data structures, greedy, math, number theory

Letter Picking

constructive algorithms, dp, games, two pointers

Mainak and the Bleeding Polygon

binary search, geometry, implementation, math

A Certain Magical Party

combinatorics, data structures, greedy, sortings

Almost Perfect

combinatorics, fft, math

Edge Split

brute force, constructive algorithms, dfs and similar, dsu, graphs, probabilities, trees

Moving Both Hands

dp, graphs, shortest paths

Lemper Cooking Competition

data structures

Kingdom of Criticism

data structures, dsu

Journey

dp, trees

Imitating the Key Tree

combinatorics, dsu, trees

Hot Black Hot White

constructive algorithms, math

Field Photography

bitmasks, data structures, sortings

Electrical Efficiency

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

Deducing Sortability

binary search, bitmasks, math

Circular Mirror

binary search, combinatorics, geometry, math, two pointers

L-shapes

dfs and similar, implementation

Counting Rectangles

brute force, data structures, dp, implementation

Matching Reduction

brute force, constructive algorithms, dfs and similar, flows, graph matchings, graphs, interactive

Prefix Function Queries

dfs and similar, dp, hashing, string suffix structures, strings, trees

Maximum AND

bitmasks, dfs and similar, divide and conquer, greedy, sortings

Misha and Paintings

constructive algorithms, data structures, greedy, implementation, math

Xor-Subsequence (hard version)

bitmasks, data structures, dp, strings, trees

Xor-Subsequence (easy version)

bitmasks, brute force, dp, strings, trees, two pointers

Burenka, an Array and Queries

data structures, math, number theory

Impressionism

constructive algorithms, graphs, implementation, math

Permutation for Burenka

data structures, graph matchings, greedy, math, trees

Tonya and Burenka-179

data structures, greedy, math, number theory

Fibonacci Strings

greedy, implementation, math, number theory

Burenka and Traditions (hard version)

data structures, dp, greedy

Burenka and Traditions (easy version)

dp, greedy

Madoka and The First Session

constructive algorithms, flows, graph matchings, graphs, implementation

Madoka and The Best University

math, number theory

Madoka and The Corruption Scheme

combinatorics, constructive algorithms, greedy, math

Bags with Balls

combinatorics, dp, math, number theory

Swap and Maximum Block

bitmasks, data structures, dfs and similar, divide and conquer, dp

Chip Move

brute force, dp, math

Robot in a Hallway

data structures, dp, greedy, implementation, ternary search

Crop Squares

constructive algorithms, geometry, interactive, math

Long Way Home

data structures, divide and conquer, dp, geometry, graphs, greedy, shortest paths

2+ doors

2-sat, bitmasks, graphs, greedy

Monoblock

combinatorics, data structures, implementation, math

Path Prefixes

binary search, data structures, dfs and similar, trees

Build a Tree and That Is It

constructive algorithms, implementation, trees

Color with Occurrences

brute force, data structures, dp, greedy, strings

Lost Array

bitmasks, combinatorics, constructive algorithms, dp, math

Cross Swapping

2-sat, data structures, dsu, greedy, matrices

Tournament Countdown

constructive algorithms, greedy, interactive, number theory, probabilities

Triameter

binary search, data structures, dfs and similar, trees

LCM Sum (hard version)

brute force, data structures, math, number theory, two pointers

LCM Sum (easy version)

binary search, brute force, combinatorics, math, number theory, two pointers

Empty Graph

binary search, constructive algorithms, data structures, greedy, shortest paths

Two Arrays

binary search, games, graph matchings

Recover the Tree

constructive algorithms, trees

XOR Triangle

bitmasks, brute force, constructive algorithms, dp, greedy, math

Rain

binary search, brute force, data structures, geometry, greedy, implementation, math

Multiset of Strings

bitmasks, brute force, dp, fft, flows, graphs, math, meet-in-the-middle, trees

XOR Tree

bitmasks, data structures, dfs and similar, dsu, greedy, trees

Rorororobot

binary search, data structures, greedy, math

Recover an RBS

constructive algorithms, greedy, implementation, strings

Bugaboo

bitmasks, constructive algorithms, dp, number theory

Replace

binary search, data structures

Partial Virtual Trees

combinatorics, dfs and similar, dp, math, trees

DFS Trees

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

Difference Array

brute force, data structures, implementation, sortings

Doremy's IQ

binary search, constructive algorithms, greedy, implementation

Qpwoeirut and Vertices

binary search, data structures, dfs and similar, divide and conquer, dsu, greedy, trees

Chopping Carrots (Hard Version)

brute force, constructive algorithms, data structures, dp, greedy, math, number theory, two pointers