Fallen Leaves

dfs and similar, dp, dp, trees, trees

Drowning

binary search, data structures, math

It Just Keeps Going Sideways

binary search, data structures, data structures, dp, dp, greedy, greedy, math, math

It All Went Sideways

binary search, data structures, dp, greedy

Palindromex

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

Snowfall

constructive algorithms, math

Party Monster

greedy

Koshary

implementation, math

Stop Spot

strings, trees

Inversion Invasion

math, number theory

Mental Monumental (Hard Version)

data structures, greedy, math, two pointers

Reserved Reversals

constructive algorithms, dp, greedy, math

Mental Monumental (Easy Version)

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

Everything Everywhere

greedy, math, math, number theory, number theory

Disturbing Distribution

greedy, math

Simple Problem

brute force, graphs, greedy, number theory

String Cutting

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

Covering Points with Circles

constructive algorithms, geometry, math

Exceptional Segments

bitmasks, brute force, math

Red-Black Pairs

dp, greedy

Alternating String

brute force, greedy

A Number Between Two Others

greedy, math

Counting Sort?

brute force, combinatorics, dp

Statistics on Tree

binary search, brute force, dfs and similar, dfs and similar, divide and conquer, graphs, trees, trees

Building Tree

data structures, divide and conquer, dsu, graphs, graphs, implementation

Seek the Truth

binary search, bitmasks, constructive algorithms, interactive

Permutation Construction

constructive algorithms, data structures, sortings

Median Partition

dp, math

Artistic Balance Tree

greedy, sortings

A Wonderful Contest

brute force, dp, math

OIE Excursion

greedy

Blocked

greedy, sortings

Weird Chessboard

constructive algorithms, math

MEX Replacement on Tree

data structures, implementation, math, trees

Coloring a Red Black Tree

dfs and similar, dp, greedy, math, probabilities, trees, trees

Unique Values (Hard version)

binary search, bitmasks, constructive algorithms, interactive

Unique Values (Easy version)

binary search, constructive algorithms, divide and conquer, interactive, math

Grid L

brute force, constructive algorithms, math, number theory

The 67th Iteration of "Counting is Fun"

implementation, math

The 67th Tree Problem

constructive algorithms, implementation, trees

The 67th XOR Problem

binary search, bitmasks, brute force

The 67th OEIS Problem

constructive algorithms, greedy, greedy, greedy, math, math, number theory

The 67th Permutation Problem

constructive algorithms, greedy, math

The 67th 6-7 Integer Problem

greedy, math

The 67th Integer Problem

brute force, games, implementation, math

Closer

dfs and similar, dp, trees

Down the Pivot

combinatorics, dp, math, trees

Interval Game

bitmasks, combinatorics, constructive algorithms, dp, games, games, greedy, greedy, math, probabilities

Definitely Larger

binary search, constructive algorithms, data structures, graphs, greedy, sortings

Flip the Bit (Hard Version)

greedy, implementation, math

Grid Covering

chinese remainder theorem, math, number theory

Flip the Bit (Easy Version)

greedy, implementation

The Equalizer

math

THU Packing Puzzle

greedy

Course Wishes

greedy

Maze

trees

Research

games

Star Map

constructive algorithms, data structures, geometry, greedy, sortings

EXPloration, EXPloitation, and Gain Some EXPerience!

bitmasks, brute force, dp, greedy, implementation

Oriented Journey

bitmasks, brute force, communication, constructive algorithms, graphs, interactive, trees

RReeppeettiittiioonn

binary search, brute force, implementation, math, number theory

Interval Mod

constructive algorithms, dp, greedy, math

Special Problem

*special problem, brute force, games, interactive

You Are a Robot

*special problem, *special problem

Double Vision

*special problem

Anomaly

*special problem, communication

Numbers

*special problem

Shortest Paths

*special problem, shortest paths

Neural Feud

*special problem, strings

And?

*special problem, bitmasks

Are You Smiling?

*special problem, *special problem, *special problem, strings

Odd One Out

*special problem, graph matchings, implementation

Median Deletion

Rational Bubble Sort

constructive algorithms, geometry, greedy

Learning Binary Search

combinatorics, divide and conquer, dp, math

Minimum Path Cover

brute force, dp, greedy, interactive, interactive, math, number theory, trees

AND-array

bitmasks, combinatorics, math

Equal Multisets (Hard Version)

constructive algorithms, dsu, greedy

Equal Multisets (Easy Version)

binary search, brute force, greedy, two pointers

Mickey Mouse Constructive

constructive algorithms, dp, greedy, math

Antimedian Deletion

implementation, math

A Simple Problem

binary search, data structures, greedy, math, trees

Binary Strings are Simple?

constructive algorithms, implementation, interactive, number theory

A Simple RBS Problem

constructive algorithms, math, strings, trees

A Simple GCD Problem (Hard Version)

dp, greedy, number theory

A Simple GCD Problem (Easy Version)

greedy, number theory

Simply Sitting on Chairs

data structures, greedy

A Simple Sequence

constructive algorithms, dp, greedy, number theory

Dynamic Values And Maximum Sum

data structures, data structures, greedy, implementation, trees

A Trivial String Problem

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

Ghostfires

constructive algorithms, greedy

Find the Zero

constructive algorithms, interactive

Array

greedy

Flip Flops

greedy

Counting Cute Arrays

combinatorics, dp

Tree Orientation (Hard Version)

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

Tree Orientation (Easy Version)

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

Stamina and Tasks

dp, greedy, math

Cyclists

brute force, games, greedy, implementation, math, sortings

Bingo Candies

constructive algorithms, math