XORificator

bitmasks, brute force, greedy, hashing

Card Pairing

dp, greedy, hashing, implementation

Division + LCP (hard version)

binary search, brute force, data structures, dp, hashing, math, string suffix structures, strings

Division + LCP (easy version)

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

Frequency Mismatch (Hard Version)

binary search, data structures, dfs and similar, hashing, probabilities, trees

Frequency Mismatch (Easy Version)

binary search, data structures, divide and conquer, hashing, probabilities, trees

No Palindromes

brute force, constructive algorithms, divide and conquer, greedy, hashing, implementation, math, strings

Shuffling Songs

bitmasks, dfs and similar, dp, graphs, hashing, implementation, strings

Non-Palindromic Substring

hashing, implementation, math, strings

Shrink-Reverse

binary search, brute force, greedy, hashing, implementation, string suffix structures, strings

Light Bulbs (Hard Version)

combinatorics, data structures, dfs and similar, dp, graphs, hashing

Palindromic Problem

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

Pumping Lemma

hashing, strings

Button Pressing

bitmasks, constructive algorithms, hashing

Yarik and Musical Notes

hashing, math, number theory

Torn Lucky Ticket

brute force, dp, hashing, implementation, math

Minimum Array

binary search, brute force, constructive algorithms, data structures, greedy, hashing, two pointers

Most Different Tree

brute force, constructive algorithms, dfs and similar, greedy, hashing

Binary String Copying

binary search, brute force, data structures, hashing, strings

Character Blocking

data structures, hashing, implementation

Hyperregular Bracket Strings

combinatorics, greedy, hashing, math, number theory, sortings

Palindrome Partition

binary search, brute force, data structures, dp, hashing, strings

Gasoline prices

data structures, divide and conquer, dsu, hashing, trees

Symmetree

dfs and similar, hashing, implementation, trees

Dasha and Nightmares

bitmasks, hashing, meet-in-the-middle, strings

Remove Two Letters

data structures, greedy, hashing, strings

Labeling the Tree with Distances

data structures, dp, greedy, hashing, implementation, trees

Fixed Prefix Permutations

binary search, bitmasks, data structures, hashing, math, sortings

Delicious Dessert

binary search, dsu, hashing, math, number theory, string suffix structures

BinCoin

binary search, divide and conquer, hashing, implementation, probabilities, trees

Hossam and Range Minimum Query

binary search, bitmasks, data structures, hashing, probabilities, strings, trees

Kazaee

data structures, hashing, probabilities

Antifibonacci Cut

bitmasks, combinatorics, constructive algorithms, data structures, dp, hashing, math

Meta-set

brute force, combinatorics, data structures, hashing, math

Even Subarrays

bitmasks, brute force, hashing, math, number theory

Cut Substrings

combinatorics, dp, hashing, strings, two pointers

Kirei and the Linear Function

hashing, math

Prefix Function Queries

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

Magical Array

constructive algorithms, hashing, implementation, math

Required Length

brute force, dfs and similar, dp, hashing, shortest paths

Preorder

combinatorics, divide and conquer, dp, dsu, hashing, sortings, trees

Gojou and Matrix Game

data structures, dp, games, hashing, implementation, math, number theory, sortings

Minimal String Xoration

bitmasks, data structures, divide and conquer, greedy, hashing, sortings, strings

Weight of the System of Nested Segments

greedy, hashing, implementation, sortings

Two Arrays

bitmasks, brute force, combinatorics, greedy, hashing, math, two pointers

Fibonacci Additions

brute force, data structures, hashing, implementation, math

Masha-forgetful

brute force, constructive algorithms, dp, hashing, implementation, strings

Quadratic Set

constructive algorithms, hashing, math, number theory

Two Sequences

data structures, hashing, string suffix structures

AmShZ Wins a Bet

data structures, greedy, hashing

Alphabetic Tree

binary search, data structures, dfs and similar, hashing, string suffix structures, strings, trees

Mars

hashing

The Sum of Good Numbers

hashing, math, string suffix structures, strings

The Strongest Build

binary search, brute force, data structures, dfs and similar, graphs, greedy, hashing, implementation

Palindromic Hamiltonian Path

brute force, dfs and similar, dp, graphs, hashing

Playoff Restoration

bitmasks, brute force, hashing, implementation, meet-in-the-middle

Common Divisor Graph

brute force, constructive algorithms, dsu, graphs, hashing, math, number theory

Reverse String

brute force, dp, hashing, implementation, strings

Funny Substrings

data structures, hashing, implementation, matrices, strings

Erase and Extend (Hard Version)

binary search, data structures, greedy, hashing, string suffix structures, strings, two pointers

Erase and Extend (Easy Version)

binary search, brute force, dp, greedy, hashing, implementation, string suffix structures, strings, two pointers

Diluc and Kaeya

data structures, dp, hashing, number theory

String Distance

binary search, brute force, data structures, hashing, implementation, strings

String Searching

*special problem, hashing

Sequence Pair Weight

hashing, implementation, math

Same Differences

data structures, hashing, math

Going Home

brute force, hashing, implementation, math

A-Z Graph

constructive algorithms, data structures, graphs, hashing

GCD of an Array

brute force, data structures, hashing, implementation, math, number theory, sortings, two pointers

Minimum Difference

data structures, hashing, sortings, two pointers

Pattern Matching

bitmasks, data structures, dfs and similar, graphs, hashing, sortings, strings

Strange Definition

bitmasks, graphs, hashing, math, number theory

A Bit Similar

bitmasks, brute force, hashing, string suffix structures, strings, two pointers

Full Turn

geometry, hashing, number theory

Song of the Sirens

combinatorics, divide and conquer, hashing, math, string suffix structures, strings

String Equality

dp, greedy, hashing, implementation, strings

Three Occurrences

data structures, divide and conquer, hashing, two pointers

Boboniu Walks on Graph

brute force, dfs and similar, graphs, hashing

Twilight and Ancient Scroll (harder version)

dp, hashing, implementation, string suffix structures, strings, two pointers

Twilight and Ancient Scroll (easier version)

dp, hashing, implementation, string suffix structures, strings

Spy-string

bitmasks, brute force, constructive algorithms, dp, hashing, strings

Nastya and CBS

brute force, data structures, hashing

Prefix-Suffix Palindrome (Hard version)

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

Prefix-Suffix Palindrome (Easy version)

hashing, string suffix structures, strings

Instant Noodles

graphs, hashing, math, number theory

Reachable Strings

data structures, hashing, strings

Concatenation with intersection

data structures, hashing, strings, two pointers

Madhouse (Hard version)

brute force, constructive algorithms, hashing, interactive, math

New Year and Conference

binary search, data structures, hashing, sortings

Let's Play the Words?

data structures, hashing, implementation, math

Make Them Similar

bitmasks, brute force, hashing, meet-in-the-middle

Regular Forestation

hashing, trees

Complete Tripartite

brute force, constructive algorithms, graphs, hashing, implementation

Power Products

hashing, math, number theory

Stack Exterminable Arrays

data structures, divide and conquer, dp, hashing

Treasure Island

dfs and similar, dp, flows, hashing

Indie Album

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

Compress Words

brute force, hashing, implementation, string suffix structures, strings

Complete Mirror

constructive algorithms, dfs and similar, dp, hashing, implementation, trees

The Number of Subpermutations

brute force, data structures, divide and conquer, hashing, math