Create The Teams

Berserk And Fireball

Merging Towers

Strange Addition

Circular Dungeon

贪心 · 排序 · 逆元

Prefix Flip (Hard Version)

构造

Prefix Flip (Easy Version)

构造

Unmerge

Mastermind

构造

The Majestic Brown Tree Snake

贪心 · 树论 · Ad-hoc

Origami

Common Subsequence

Sequential Nim

String Transformation 1

GameGame

String Transformation 2

Rearrange

贪心 · 排序 · 构造

Strange Operation

Special Edges

Common Prefixes

Koa and the Beach (Hard Version)

Koa and the Beach (Easy Version)

Three Pairwise Maximums

Restore the Permutation by Merger

Make It Good

a-Good String

分治

Directing Edges

图论 · 拓扑排序

Removing Leaves

Columns Swaps

并查集 · 图论建模 · 二分图 · 基环树

Colors

2020 · BalticOI（波罗的海）

Mixture

2020 · BalticOI（波罗的海）

Joker

2020 · BalticOI（波罗的海）

Graph

2020 · BalticOI（波罗的海）

Village (Maximum)

贪心 · 树形数据结构

Village (Minimum)

Viruses

2020 · BalticOI（波罗的海）

Captain Flint and Crew Recruitment

Captain Flint and a Long Voyage

Uncle Bogdan and Country Happiness

图论

Captain Flint and Treasure

贪心 · 深度优先搜索 DFS

Uncle Bogdan and Projections

LCM Problem

Array Walk

Good String

Segment Intersections

Calendar Ambiguity

Bicolored Segments

Directing Edges

Suborrays

Fix You