Railway System

生成树

Sanae and Giant Robot

并查集 · 广度优先搜索 BFS

Cute number

数学 · 数论

Become Big For Me

数论 · 容斥原理 · 构造

Koishi's Unconscious Permutation

生成函数

Cirno's Perfect Bitmasks Classroom

位运算

Patchouli's Magical Talisman

贪心 · 位运算

Manipulating History

位运算

Lex String

Mystic Permutation

Infected Tree

Lena and Matrix

ANDfinity

Print a Pedestal (Codeforces logo?)

Array Decrements

Restoring the Duration of Tasks

Black and White Stripe

Price Maximization

Shifting String

Count the Trains

线段树

Beat The Odds

Shoe Shuffling

Sum of Substrings

Max GEQ Sum

线段树 · ST 表 · 单调栈

Number of Groups

K-Set Tree

树形 DP

Marathon

All Distinct

Where's the Bishop?

The Clock

Binary Deque

3SUM

2^Sort

Gambling

Directional Increase

Fake Plastic Trees

贪心 · 树形数据结构

Keshi in Search of AmShZ

动态规划 DP · 图论 · 贪心 · 博弈论 · 最短路

Decinc Dividing

Outermost Maximums

I Might Be Wrong

Creep

Paranoid String

Subrectangle Guess

Circle Game

Zero Path

Tree Queries (Hard Version)

Tree Queries (Easy Version)

Ambiguous Dominoes

欧拉回路

NIT orz!

贪心 · 位运算

NIT Destroys the Universe

贪心