LuoTianyi and the Floating Islands (Hard Version)

combinatorics, dfs and similar, math, probabilities, trees

LuoTianyi and the Floating Islands (Easy Version)

combinatorics, math, probabilities, trees

Random Walk

dp, graphs, math, probabilities, trees

Gardening Friends

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

Roads in E City

interactive, math, probabilities, trees

The Fox and the Complete Tree Traversal

constructive algorithms, dp, implementation, math, trees

Sum Graph

brute force, constructive algorithms, graphs, implementation, interactive, shortest paths, trees

M-tree

data structures, math, sortings, trees

Tree Master

brute force, data structures, dfs and similar, trees

There Should Be a Lot of Maximums

brute force, data structures, dfs and similar, dp, trees, two pointers

A Wide, Wide Graph

dfs and similar, dp, graphs, greedy, trees

Gasoline prices

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

Symmetree

dfs and similar, hashing, implementation, trees

Li Hua and Path

data structures, dfs and similar, divide and conquer, dsu, trees

Li Hua and Tree

brute force, data structures, dfs and similar, dp, implementation, trees

Colored Subgraphs

dfs and similar, dp, games, greedy, trees

Blocking Chips

binary search, constructive algorithms, dfs and similar, greedy, trees

Labeling the Tree with Distances

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

Timofey and Black-White Tree

brute force, dfs and similar, divide and conquer, graphs, greedy, math, shortest paths, trees

XOR, Tree, and Queries

bitmasks, constructive algorithms, dfs and similar, dsu, graphs, greedy, implementation, trees

Colorful Tree Again

brute force, data structures, trees

Weighed Tree Radius

data structures, divide and conquer, implementation, trees

Diverse Coloring

constructive algorithms, trees

Bracket Insertion

combinatorics, dp, math, trees

Xorcerer's Stones

bitmasks, constructive algorithms, dp, trees

Maximizing Root

dfs and similar, dp, graphs, math, number theory, trees

The Tree Has Fallen!

bitmasks, dfs and similar, math, trees

Comfortably Numb

bitmasks, data structures, divide and conquer, strings, trees

Edge Reverse

binary search, dfs and similar, graphs, trees

Score of a Tree

bitmasks, combinatorics, dfs and similar, dp, math, probabilities, trees

Parmigiana With Seafood

binary search, dp, greedy, trees

Segment Covering

brute force, combinatorics, constructive algorithms, data structures, dp, trees

Two Chess Pieces

dfs and similar, dp, greedy, trees

BinCoin

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

Hossam and Range Minimum Query

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

Hossam and (sub-)palindromic tree

brute force, data structures, dfs and similar, dp, strings, trees

Koxia and Tree

combinatorics, dfs and similar, dp, dsu, math, probabilities, trees

Two Subtrees

data structures, trees

Algebra Flash

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

Doremy's Experimental Tree

brute force, constructive algorithms, dfs and similar, dsu, sortings, trees

Edge Queries

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

Tree Sum

combinatorics, math, trees

Centroid Guess

interactive, probabilities, trees

Make It Connected

binary search, brute force, constructive algorithms, dsu, graphs, greedy, matrices, trees, two pointers

Distance to the Path

data structures, dfs and similar, trees

Yet Another Array Counting Problem

binary search, data structures, divide and conquer, dp, flows, math, trees

Paths on the Tree

dfs and similar, dp, greedy, sortings, trees

Masha and a Beautiful Tree

dfs and similar, divide and conquer, graphs, sortings, trees

MEX Tree Manipulation

data structures, trees

Hanging Hearts

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

Reset K Edges

binary search, data structures, dfs and similar, graphs, greedy, trees

Connectivity Addicts

constructive algorithms, dsu, graphs, greedy, interactive, shortest paths, trees

Permutation Addicts

constructive algorithms, data structures, dfs and similar, dsu, graphs, trees

Edge Split

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

Journey

dp, trees

Imitating the Key Tree

combinatorics, dsu, trees

Electrical Efficiency

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

Prefix Function Queries

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

Xor-Subsequence (hard version)

bitmasks, data structures, dp, strings, trees

Xor-Subsequence (easy version)

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

Permutation for Burenka

data structures, graph matchings, greedy, math, trees

Path Prefixes

binary search, data structures, dfs and similar, trees

Build a Tree and That Is It

constructive algorithms, implementation, trees

Triameter

binary search, data structures, dfs and similar, trees

Recover the Tree

constructive algorithms, trees

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

Partial Virtual Trees

combinatorics, dfs and similar, dp, math, trees

DFS Trees

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

Qpwoeirut and Vertices

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

Passable Paths (hard version)

data structures, dfs and similar, trees

Passable Paths (easy version)

dfs and similar, trees

PermutationForces II

brute force, combinatorics, greedy, sortings, trees, two pointers

Tree Recovery

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

Tree Queries (Hard Version)

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

Tree Queries (Easy Version)

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

Fake Plastic Trees

dfs and similar, dp, greedy, trees

K-Set Tree

combinatorics, dfs and similar, dp, math, trees

Infected Tree

dfs and similar, dp, trees

Unordered Swaps

constructive algorithms, dfs and similar, graphs, greedy, math, sortings, trees

Circular Spanning Tree

constructive algorithms, implementation, trees

Unique Occurrences

data structures, dfs and similar, divide and conquer, dp, dsu, trees

Lenient Vertex Cover

dfs and similar, divide and conquer, dsu, graphs, trees

White-Black Balanced Subtrees

dfs and similar, dp, graphs, trees

Vlad and Unfinished Business

dfs and similar, dp, greedy, trees

Vertical Paths

graphs, implementation, trees

Preorder

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

Hemose on the Tree

bitmasks, constructive algorithms, dfs and similar, trees

Edge Elimination

constructive algorithms, dfs and similar, dp, trees

Job Lookup

constructive algorithms, dp, shortest paths, trees

Tree Infection

binary search, greedy, sortings, trees

Who Tested?

*special problem, expression parsing, trees

Gastronomic Event

dp, greedy, trees

Narrow Components

brute force, data structures, dp, dsu, math, trees

Tree and Permutation Game

dfs and similar, games, graphs, trees

Words on Tree

2-sat, dfs and similar, dsu, graphs, trees

Equal Tree Sums

constructive algorithms, dfs and similar, math, trees

Snowy Mountain

data structures, dfs and similar, graphs, greedy, shortest paths, trees

Potion Brewing Class

dfs and similar, math, number theory, trees

Air Reform

data structures, dfs and similar, divide and conquer, dsu, graphs, implementation, trees