Four Stones

constructive algorithms

Standard Graph Problem

data structures, graphs, greedy, trees

Anti-median (Hard Version)

combinatorics, dp, math

Koishi's Unconscious Permutation

fft, math

Long Recovery

constructive algorithms, dfs and similar

Cubic Lattice

geometry, math, matrices, number theory

Game of AI (hard version)

combinatorics, fft, math

Jellyfish Nightmare

Minimum Hamming Distance

dp

AquaMoon and Time Stop (easy version)

data structures, dp

Min-Sum-Max

constructive algorithms, dp, greedy

Ruler Of The Zoo

brute force, data structures

Jellyfish and Inscryption

dp

BinaryStringForces

constructive algorithms, data structures, dp

Goldberg Machine 3

dp, trees

Three Minimums

combinatorics, constructive algorithms, divide and conquer, dp, fft, math

Spiderweb Trees

dp, geometry, trees

LIS?

data structures, greedy, implementation

Redundant Routes

constructive algorithms, dp, trees

Prison Break

binary search, games, geometry, ternary search

Doremy's Average Tree

data structures, dp, greedy, trees

Wakanda Forever

Count Permutations

math

Fly Around the World

dp, geometry

Crossing the Railways

data structures, dp

Heroes of Might

math

Parallel Swaps Sort

constructive algorithms, data structures

Farmer John's Favorite Intern

data structures, dp, flows, trees

Counting Is Fun

combinatorics

Zig-zag

Antiparticle Antiphysics

Game of Chance

math, probabilities

Lisa's Sequences

dp

Cactus Meets Torus

Cactus Lady and her Cing