Red-Blue Graph

dp, graphs, math, matrices, meet-in-the-middle

Permutation Concatenation

string suffix structures

Almost Same Distance

dfs and similar, graphs

Spaceship Solitaire

data structures, greedy, implementation

Decreasing Debts

constructive algorithms, data structures, graphs, greedy, implementation, math, two pointers

Diverse Matrix

constructive algorithms, greedy, math, number theory

Beautiful Mirrors

data structures, dp, math, probabilities

Beautiful Fibonacci Problem

constructive algorithms, number theory

Beautiful League

constructive algorithms, flows, graph matchings

Beautiful Bracket Sequence (hard version)

combinatorics, probabilities

Beautiful Bracket Sequence (easy version)

combinatorics, dp, probabilities

Beautiful Mirrors with queries

data structures, probabilities

Beautiful Sequence

brute force, constructive algorithms, greedy

Beautiful Regional Contest

greedy, implementation

Economic Difficulties

data structures, dfs and similar, dp, flows, graphs, trees

Editor

data structures, implementation

Secret Passwords

dfs and similar, dsu, graphs

Everyone is a Winner!

binary search, math, meet-in-the-middle, number theory

PIN Codes

greedy, implementation

Xor-Set

bitmasks, divide and conquer, math

Colored Tree

data structures, trees

Tournament

brute force, dp, greedy

A Game with Traps

binary search, dp, greedy, sortings

Infinite Fence

greedy, math, number theory

Divisor Set

divide and conquer, fft, greedy, math, number theory

Make Them Similar

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

The Contest

data structures, dp, greedy

Yet Another Monster Killing Problem

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

Equalizing Two Strings

constructive algorithms, sortings, strings

Yet Another Division Into Teams

dp, greedy, sortings

Binary String Minimizing

greedy

Platforms Jumping

greedy

Minimize the Permutation

greedy

League of Leesins

constructive algorithms, implementation

Send Tree to Charlie

combinatorics, dfs and similar, dsu, trees

Tree Queries

data structures, probabilities, trees

Point Ordering

constructive algorithms, geometry, interactive, math

Send Boxes to Alice (Hard Version)

constructive algorithms, greedy, math, number theory, ternary search, two pointers

Send Boxes to Alice (Easy Version)

constructive algorithms, greedy, math, number theory, ternary search, two pointers

Feeding Chicken

constructive algorithms, greedy, implementation

Cheap Robot

binary search, dsu, graphs, shortest paths, trees

Antenna Coverage

data structures, dp, greedy, sortings

Harmonious Graph

constructive algorithms, dfs and similar, dsu, graphs, greedy, sortings

Sweets Eating

dp, greedy, math, sortings

Silly Mistake

greedy, implementation

Road Construction

flows, graphs

Addition Robot

data structures, math, matrices

Tiling Terrace

brute force, dp

Mission Possible

Twin Buildings

greedy, implementation

Performance Review

data structures

Regular Forestation

hashing, trees

Songwriter

greedy, two pointers

Find String in a Grid

data structures, dp, strings, trees

Even Path

data structures, implementation

Cleaning Robots

dp, trees

Red-White Fence

combinatorics, fft

Voting (Hard Version)

binary search, data structures, greedy

Voting (Easy Version)

data structures, dp, greedy

Salary Changing

binary search, greedy, sortings

Minimize The Integer

greedy, two pointers

Binary Palindromes

greedy, strings

Wires

dfs and similar, graphs, greedy

SmartGarden

constructive algorithms, divide and conquer

Divide The Students

binary search, greedy, math

Projectors

flows, graphs

The Parade

binary search, greedy

Show Must Go On

binary search, brute force, greedy, shortest paths

Happy Birthday

math

Discarding Game

dp, greedy, two pointers

The Coronation

graphs, implementation

Conference Problem

dp

Trip to Saint Petersburg

data structures

The Feast and the Bus

brute force, constructive algorithms, greedy, math

Berstagram

implementation

Maximum Weight Subset

dp, trees

By Elevator or Stairs?

dp, shortest paths

Too Many Segments (hard version)

data structures, greedy, sortings

Too Many Segments (easy version)

greedy

Good Numbers (hard version)

binary search, greedy, math, meet-in-the-middle

The World Is Just a Programming Task (Easy Version)

brute force, dp, greedy, implementation

Cursor Distance

Daniel and Spring Cleaning

bitmasks, brute force, combinatorics, dp

Hyakugoku and Ladders

dp, probabilities, shortest paths

Shichikuji and Power Grid

dsu, graphs, greedy, shortest paths, trees

Constanze's Machine

dp

Running in Pairs

constructive algorithms, greedy, math

Chips

constructive algorithms, implementation

Minimizing Difference

binary search, constructive algorithms, greedy, sortings, ternary search, two pointers

Paint the Tree

brute force, constructive algorithms, dp, graphs, implementation, trees

The Football Season

brute force, math, number theory

Character Swap (Hard Version)

strings

Planar Perimeter

constructive algorithms, graphs

Number Discovery

math

Sum Balance

bitmasks, dfs and similar, dp, graphs

0-1 MST

dfs and similar, dsu, graphs, sortings

Tile Painting

constructive algorithms, math, number theory

Football

graphs

Swiper, no swiping!

graphs, implementation

Turtle

dp, implementation