Problems

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Total results29,295 problems

Rabid Rabbit
Medium6
Hash map, Intervals+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Fellow Sheep
Medium6
Graph, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Watchdogs
Medium6
Tree, Dynamic programming
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Annoying Alliterations
Medium6
Trie, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Grocery Greed
Medium6
Math, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Karaoke Compression
Medium6
String, String matching+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Beaking Spackwards
Medium6
String, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Feline Friendship
Medium6
Graph, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gridlock
Medium6
Topological sort, Greedy+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Eight 2 Zero
Medium6
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sogang Pizza
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Water Tank
Medium6
Simulation, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Square Queries
Medium6
Hash map, Prefix sum+1
No attempts yet
Time limit
4.5s
Memory limit
1024 MB
Judgeable
Filling the Tree
Medium6
Greedy, Tree+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Destroyer King Ttungppup
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
GLCCDM
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wuzhangyuan
Medium6
Dynamic programming, Game theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ardi, The Hungry Aardvark
Medium6
Dynamic programming, Tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Palindromic Word Search
Medium6
String matching, Matrix+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Pillow Stacking
Medium6
Dynamic programming, Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Rocky Mountain
Medium6
Geometry, Stack
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
N-Rock-Paper-Scissors
Medium6
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Starlight Express
Medium6
Hash map, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Team Formation
Medium6
Sorting, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Symmetry
Medium6
Matrix, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Quality of Life Index
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dial Roulette
Medium6
Array, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Air Raid Shelter
Medium6
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Priority Queue and Simulation
Medium6
Sorting, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Perfect City Design
Medium6
Graph, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mixed Output
Medium6
Backtracking, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Card Pairs
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Thanos Snap
Medium6
Divide and conquer, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rock-Paper-Scissors Tiles
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Please Pay Me 998244353 Won
Medium6
Greedy, Math+1
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Auto-Coin-o-Matic
Medium6
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Sleeping on the Train
Medium6
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Brownian Bears
Medium6
Probability, Math+1
No attempts yet
Time limit
4s
Memory limit
2048 MB
Judgeable
Marching Orders
Medium6
Number theory, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Repetitive Routes
Medium6
Intervals, Prefix sum+1
No attempts yet
Time limit
8s
Memory limit
2048 MB
Judgeable
Cleaning Robot
Medium6
Simulation, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Diagonal Flipping
Medium6
Union-find, Graph+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Mining Rights Division
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
New Megacity
Medium6
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
2.5s
Memory limit
2048 MB
Judgeable
Polygon Discovery
Medium6
Geometry, Math+1
No attempts yet
Time limit
4s
Memory limit
2048 MB
Judgeable
Cards Flipping
Medium6
Union-find, Graph
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Square Stamping
Medium6
Greedy, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Street Development
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Elevated Rails
Medium6
Tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Optimized Cheating
Medium6
BFS, Hash map+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Memories of Passport Stamps
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Anyone Can Solve It
Medium6
Dynamic programming, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
HCPC Team Formation
Medium6
Combinatorics, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Black and White Landscaper
Medium6
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Games
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tree
Medium6
Tree, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Flowing Fountain
Medium6
Stack, Union-find+1
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
Hash Collision
Medium6
Graph, Math
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Limited Library
Medium6
Greedy, Binary search+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Count the Operations
Medium6
Simulation, Graph+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Brick in the Wall, Part 2
Medium6
Graph, BFS+1
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
If I Could Turn Back Time
Medium6
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
I Don't Want to Work
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bountiful Tree
Medium6
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Time Machine
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wrong LIS Algorithm
Medium6
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Partial Sums of a Triangle
Medium6
Prefix sum, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Packing Luggage
Medium6
Greedy, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tree Reading
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Run-up Jump
Medium6
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Heavy rain (Easy)
Medium6
Array, Segment tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Karte
Medium6
Bit manipulation, Brute force
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
I love winter
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
I Hate Raisins
Medium6
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Graph Products
Medium6
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Omnes Viae Yokohamam Ducunt?
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Greatest of the Greatest Common Divisors
Medium6
Number theory, Sorting+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Scheduling Two Meetings
Medium6
Bit manipulation, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
The ellipse with the most points on it
Medium6
Geometry, Hash map+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Joy of Pokémon Observation
Medium6
Number theory, Math+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
DAG Serialization
Medium6
Topological sort, Graph+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Geometric Balance
Medium6
String matching, Math+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Deforestation
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Roundabout Rounding
Medium6
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Grid and Queries
Medium6
Segment tree, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stock Market
Medium6
Prefix sum, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Reporting Documents
Medium6
Array, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Finding Treasure
Medium6
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Critical Road
Medium6
Topological sort, Graph+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Counting Pairs
Medium6
Bit manipulation, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Three Three Three
Medium6
Game theory, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
ICPC Square
Medium6
Number theory, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Card Game
Medium6
Hash map, Sorting+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Yet Another Sequence Problem
Medium6
Hash map, Math+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
K Nations
Medium6
Dynamic programming, Tree
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mashu Vandead and the Wizard's Grid
Medium6
Math, Matrix+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Guardian of Balance
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Autocomplete
Medium6
Trie, Heap
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pistons
Medium6
Array, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Colorful Intervals
Medium6
Sliding window, Array+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Rabid RabbitFor each segment, count the distinct Fibonacci numbers that equal the sum of rabbit counts in some pair of hutches inside the segment.	Medium6	Hash mapIntervals+1	No attempts yet	10s	1024 MB	Judgeable
Fellow SheepGiven N repeated five-gate segments with gate capacities, find the maximum number of sheep that can reach the farmyard from the pasture.	Medium6	GraphDynamic programming	No attempts yet	2s	1024 MB	Judgeable
WatchdogsGiven a tree and mouse paths, find the fewest vertices that include at least one middle vertex of every path.	Medium6	TreeDynamic programming	No attempts yet	5s	1024 MB	Judgeable
Annoying AlliterationsGiven n words, find the two words whose combined length is maximized after stripping leading letters from both while their first letters match.	Medium6	TrieString+1	No attempts yet	2s	1024 MB	Judgeable
Grocery GreedGiven item prices, split the items into groups paid either by card (exact) or cash (rounded to the nearest 0.05 euro), and find the minimum total.	Medium6	MathGreedy	No attempts yet	2s	1024 MB	Judgeable
Karaoke CompressionPick one substring t, replace its non-overlapping occurrences with a new character, and output the minimum of \|t\| plus the length of the compressed string.	Medium6	StringString matching+1	No attempts yet	10s	1024 MB	Judgeable
Beaking SpackwardsBuild a lowercase string of length at most 100000 that contains exactly s palindrome substrings, where s can be up to 1e9.	Medium6	StringGreedy	No attempts yet	1s	1024 MB	Judgeable
Feline FriendshipGiven a permutation of n cats, find the fewest favourite-partner changes needed so that some cycle has length exactly k.	Medium6	GraphGreedy+1	No attempts yet	2s	1024 MB	Judgeable
GridlockGiven a grid of arrow blocks, find an order that slides every block out of the grid in its arrow direction, or report that no such order exists.	Medium6	Topological sortGreedy+1	No attempts yet	6s	1024 MB	Judgeable
Eight 2 ZeroGiven a connected graph with N nodes and N+1 links, find the fewest links to remove so that every remaining node lies on exactly one cycle.	Medium6	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
Sogang PizzaFind the smallest daily pizza count X so that each student i gets k_i pizzas by day t_i, with at most one pizza per student per day.	Medium6	Binary searchGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Water TankGiven a tank with capacity x and N add or remove operations, find the water left after applying all operations to each query's starting amount y.	Medium6	SimulationArray	No attempts yet	1s	1024 MB	Judgeable
Square QueriesFor each query, count the distinct values still present in the grid after blanking out the K by K square with the given top-left corner.	Medium6	Hash mapPrefix sum+1	No attempts yet	4.5s	1024 MB	Judgeable
Filling the TreeDecide whether the unused sticker numbers can fill a rooted tree so each parent's sticker exceeds its child's, and print one valid filling.	Medium6	GreedyTree+2	No attempts yet	1s	1024 MB	Judgeable
Destroyer King TtungppupGiven a grid of pillars that cost energy to pass and at most T teleports, answer for each query whether a cell is reachable from (1,1) within energy p.	Medium6	GraphShortest path+1	No attempts yet	1.5s	1024 MB	Judgeable
GLCCDMGiven A, B, and K, the task asks for K distinct positive integers with gcd equal to A and lcm equal to B, or -1 if none exist.	Medium6	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
WuzhangyuanGiven X, K, and C, find the minimum total cost to send X supplies in attempts costing a+C each, when Sima Yi blocks up to K attempts to maximize the cost.	Medium6	Dynamic programmingGame theory+1	No attempts yet	2s	1024 MB	Judgeable
Ardi, The Hungry AardvarkGiven recorded maximal tongue paths through a tunnel tree with ant counts, find the most ants Ardi can reach with a fixed number of probes.	Medium6	Dynamic programmingTree+1	No attempts yet	1s	1024 MB	Judgeable
Palindromic Word SearchFind the largest-area sub-rectangle of a letter grid that has a palindrome across one of its full rows and one of its full columns.	Medium6	String matchingMatrix+1	No attempts yet	6s	1024 MB	Judgeable
Pillow StackingGiven N pillow softness values and a target C, decide whether a stack of pillows (none with softness C) can reach total softness C.	Medium6	Dynamic programmingMath	No attempts yet	3s	1024 MB	Judgeable
Rocky MountainGiven a mountain range as a polyline, find the lowest site on each side of the highest peak that a straight cable can reach without crossing the range.	Medium6	GeometryStack	No attempts yet	3s	1024 MB	Judgeable
N-Rock-Paper-ScissorsGiven the opponent's card sequence, play each card 1 to N exactly once to maximize rounds where your card is not cyclically adjacent to theirs.	Medium6	GreedyMath	No attempts yet	1s	1024 MB	Judgeable
Starlight ExpressGiven N station coordinates, find an unused point that maximizes the number of connected station pairs, where stations sharing an x or y coordinate are linked.	Medium6	Hash mapUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
Team FormationGiven N members with skill and target rank, pick disjoint triples whose rank spread is at most K to maximize the total skill of the chosen triples.	Medium6	SortingDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
SymmetryCount the subgrids with an even number of columns that are mirror-symmetric across their vertical center line.	Medium6	MatrixString+1	No attempts yet	2s	1024 MB	Judgeable
Quality of Life IndexGiven countries with three indicators and pairwise ranking requirements, decide whether non-negative weights exist that make every requirement hold strictly.	Medium6	GeometryMath+1	No attempts yet	1s	1024 MB	Judgeable
Dial RouletteGiven a circular sequence A of length N, find the maximum sum of numbers passed when the dial is rotated K times.	Medium6	ArraySliding window+1	No attempts yet	1s	1024 MB	Judgeable
Air Raid ShelterGiven N unit square walls, find the largest area of interior space that the walls can fully enclose.	Medium6	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Priority Queue and SimulationGiven a priority queue, add A_i to every element, reduce each element modulo K, and print the maximum after each of T queries.	Medium6	SortingSimulation	No attempts yet	1s	1024 MB	Judgeable
Perfect City DesignGiven a graph where each city has exactly one outgoing road, find the fewest road changes needed so every city can reach every other city.	Medium6	GraphGreedy	No attempts yet	1s	1024 MB	Judgeable
Mixed OutputGiven S made by interleaving N identical copies of one string, list every distinct string that could be that original copy, in lexicographic order.	Medium6	BacktrackingDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
Card PairsGiven counts of n card types, find the maximum number of trades where two cards of one type are swapped for one card of a different type.	Medium6	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Thanos SnapGiven a number with 2^N digits, find the largest number left after snapping it T times, where each snap keeps either the left or right half.	Medium6	Divide and conquerString+1	No attempts yet	1s	1024 MB	Judgeable
Rock-Paper-Scissors TilesGiven N tiles on a circle marked S, R, or P, find the fewest tiles to remove so every remaining tile beats the next one clockwise, cyclically.	Medium6	Dynamic programmingString+1	No attempts yet	1s	1024 MB	Judgeable
Please Pay Me 998244353 WonEmployee 0 earns X, and each employee k must earn more than employee k-1 and a multiple of k, so the task is to answer Q queries for the minimal salary of employee A_i.	Medium6	GreedyMath+1	No attempts yet	0.5s	512 MB	Judgeable
Auto-Coin-o-MaticCoins are removed over time, and for each query you must find the fewest coins that make amount v, or -1 if no combination works.	Medium6	Dynamic programmingImplementation	No attempts yet	2s	2048 MB	Judgeable
Sleeping on the TrainGiven a train that shuttles between stops 1 and n, find the fewest turnarounds it makes while Antonio rides from stop a to stop b, using t sleep-wake sightings to pin its position.	Medium6	MathGreedy+1	No attempts yet	2s	2048 MB	Judgeable
Brownian BearsTwo bears take random one-step walks on a line of n locations, and the task is the exact probability they share a location on at least one of d days.	Medium6	ProbabilityMath+1	No attempts yet	4s	2048 MB	Judgeable
Marching OrdersGiven n and a proposed order of professors, decide whether some m below 10^9 produces that order under the removal method, and print the smallest such m.	Medium6	Number theoryBacktracking+1	No attempts yet	1s	2048 MB	Judgeable
Repetitive RoutesSum, over all customers, how many stops during each customer's ride revisit a location already visited on that same ride.	Medium6	IntervalsPrefix sum+1	No attempts yet	8s	2048 MB	Judgeable
Cleaning RobotGiven axis-parallel rectangles, find the robot's position at five query times as it cleans their edges clockwise from R1's upper left corner.	Medium6	SimulationGeometry+1	No attempts yet	1s	1024 MB	Judgeable
Diagonal FlippingGiven a 0/1 grid, find the fewest diagonal flips (both diagonal directions) that turn every cell to 0, or report -1 if impossible.	Medium6	Union-findGraph+1	No attempts yet	1s	2048 MB	Judgeable
Mining Rights DivisionGiven chords that split a disk and two interior points, decide whether both points can lie in regions of the same two-coloring class.	Medium6	GeometryMath+1	No attempts yet	1s	2048 MB	Judgeable
New MegacityGiven n cities and m weighted roads, label each road 1 if every minimum spanning tree uses it, 2 if some do but not all, and 3 if none do.	Medium6	Minimum spanning treeUnion-find+2	No attempts yet	2.5s	2048 MB	Judgeable
Polygon DiscoveryFind the area of a hidden convex lattice polygon containing the origin, using queries that return how many times a given line crosses the polygon.	Medium6	GeometryMath+1	No attempts yet	4s	2048 MB	Judgeable
Cards FlippingEach card has a color on each side and can be flipped. Find the maximum number of distinct colors that can appear on the top sides.	Medium6	Union-findGraph	No attempts yet	1s	2048 MB	Judgeable
Square StampingGiven n points lying on the lines y = -9999, 0, and 9999, find the fewest axis-parallel squares of side 10000 that cover all of them.	Medium6	GreedyDynamic programming+1	No attempts yet	1s	2048 MB	Judgeable
Street DevelopmentGiven n robot positions on the street [0, L], find the minimum battery capacity P that lets robots merge all collected information into one robot.	Medium6	Binary searchGreedy+1	No attempts yet	1s	2048 MB	Judgeable
Elevated RailsGiven three trees on the stations, answer for each pair of stations in different trees the longest simple path possible after adding two connecting edges.	Medium6	TreeGraph+2	No attempts yet	2s	2048 MB	Judgeable
Optimized CheatingFind the fewest operations that turn Bob's currency into a value no other memory slot holds, printing the operation indices or -1 if impossible.	Medium6	BFSHash map+1	No attempts yet	1s	2048 MB	Judgeable
Memories of Passport StampsFind the smallest s so that k officers, each stamping between 0 and s pages, can produce exactly the n stamped sections in the passport.	Medium6	Binary searchGreedy+1	No attempts yet	1s	2048 MB	Judgeable
Anyone Can Solve ItGiven sequences A and B of digits 1 to 9, decide whether B can be reached from A by appending digits, where an even digit first sorts the last three elements.	Medium6	Dynamic programmingSimulation+1	No attempts yet	2s	1024 MB	Judgeable
HCPC Team FormationCount the 3-person teams where every member's preferred partner, if they have one, is also on the team.	Medium6	CombinatoricsGraph+1	No attempts yet	1s	1024 MB	Judgeable
Black and White LandscaperGiven a tree with vertices colored white or black, find every root for which each vertex with children takes the majority color of its descendants.	Medium6	TreeDFS+1	No attempts yet	2s	1024 MB	Judgeable
GamesEach game's rules must be learned once before unlimited replays, and the task asks for the maximum total rating reachable within d minutes.	Medium6	Dynamic programmingGreedy	No attempts yet	2s	1024 MB	Judgeable
TreeGiven a tree with integers on its nodes, pick two non-empty connected subgraphs with no shared node and no connecting edge, maximizing the total of their node values.	Medium6	TreeDynamic programming	No attempts yet	2s	1024 MB	Judgeable
Flowing FountainChampagne poured into a level spills into the first lower level with a larger capacity, and the task is to answer how much each level holds.	Medium6	StackUnion-find+1	No attempts yet	5s	2048 MB	Judgeable
Hash CollisionUsing a query oracle that returns f^c(r) for a hidden function f on {1..n}, find two pairs (c, r) with f^c(r) = c within a limited number of queries.	Medium6	GraphMath	No attempts yet	1s	2048 MB	Judgeable
Limited LibraryGiven shelf heights and book heights, place all books on shelves that hold x books each, and find the most shelves that can also hold an art piece taking x-y slots.	Medium6	GreedyBinary search+1	No attempts yet	2s	2048 MB	Judgeable
Count the OperationsGiven a loop over 0 to n-1 with conditional jumps i = y when i == x, count the operations performed or report -1 if the loop never ends.	Medium6	SimulationGraph+1	No attempts yet	2s	2048 MB	Judgeable
Brick in the Wall, Part 2Given a grid maze with an entrance s and exit f, find the shortest straight horizontal or vertical wall that separates them, or print -1.	Medium6	GraphBFS+1	No attempts yet	5s	2048 MB	Judgeable
If I Could Turn Back TimeGiven current heights h and an earlier record p, find the fewest erosion years that turn p into h, or -1 if the model cannot do it.	Medium6	ArrayImplementation	No attempts yet	2s	2048 MB	Judgeable
I Don't Want to WorkGiven N farm cells, M days, and K fruit types with first-harvest time, regrow time, and sale price, find the maximum money earned by day M.	Medium6	Dynamic programmingGreedy	No attempts yet	1s	1024 MB	Judgeable
Bountiful TreeGiven a tree, decide whether every node has degree 1 or 3 and all leaves are equally far from the root, then list all valid roots.	Medium6	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Time MachineFind the minimum time to reach vertex N from vertex 1 when one edge a to b rewinds the clock by c, or report x if unreachable or -inf if the time can shrink forever.	Medium6	Shortest pathGraph+1	No attempts yet	1s	1024 MB	Judgeable
Wrong LIS AlgorithmGiven N, M, and K, build a permutation of 1 to N whose LIS has length M and whose greedy output B has length K, or print -1 if none exists.	Medium6	GreedyArray+1	No attempts yet	1s	1024 MB	Judgeable
Partial Sums of a TriangleGiven a triangular grid of numbers, answer up to 500,000 queries that each ask for the sum of a sub-triangle with apex at (x, y) and height z.	Medium6	Prefix sumArray+1	No attempts yet	1s	1024 MB	Judgeable
Packing LuggagePick K pieces in total, where each extra piece of kind i gains less by A_i than the last, and find the maximum total value.	Medium6	GreedyBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Tree ReadingGiven a tree whose vertices each hold a digit from 1 to 9, sum the numbers read along the path for every ordered pair of vertices, modulo 1,000,000,007.	Medium6	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Run-up JumpGiven a grid with traps, decide whether repeated run-up and long jump moves can carry the start cell S to the end cell E.	Medium6	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
Heavy rain (Easy)Given N walls with heights, print the total rain that can be trapped after each of Q updates that raise one wall's height.	Medium6	ArraySegment tree	No attempts yet	2s	1024 MB	Judgeable
KarteChoose subsets of red and blue cards to maximize the number of COMBO pairs minus X per red card and Y per blue card.	Medium6	Bit manipulationBrute force	No attempts yet	1s	2048 MB	Judgeable
I love winterGiven N trees with A_i leaves each dropping B_i per day, and one optional double-rate day per boost, find the earliest day all leaves have fallen.	Medium6	Binary searchGreedy+1	No attempts yet	1s	1024 MB	Judgeable
I Hate RaisinsGiven an X by Y by Z cake with one hidden unit raisin, find the fewest axis-parallel cuts that pinpoint the raisin's cell in the worst case.	Medium6	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Graph ProductsGiven graphs A and B, answer queries for the shortest path from G11 to a given vertex in the Cartesian, tensor, or strong product of A and B.	Medium6	GraphBFS+2	No attempts yet	2s	1024 MB	Judgeable
Omnes Viae Yokohamam Ducunt?Find a spanning tree rooted at city 1 that minimizes the sum over edges of vulnerability times the significance total of the cities cut off from city 1 by that edge.	Medium6	Shortest pathGraph+1	No attempts yet	3s	2048 MB	Judgeable
Greatest of the Greatest Common DivisorsGiven an integer sequence and range queries, find the largest gcd over all pairs of positions inside each query range.	Medium6	Number theorySorting+1	No attempts yet	1s	2048 MB	Judgeable
Scheduling Two MeetingsGiven n time slots with a Y/N on-site mask over m judges, pick two slots whose on-site sets cover every judge and share the most on-site judges.	Medium6	Bit manipulationDynamic programming	No attempts yet	1s	2048 MB	Judgeable
The ellipse with the most points on itGiven N integer points, find the most of them that can lie on one origin-centered ellipse (x/a)^2 + (y/b)^2 = c^2 with nonzero a and b.	Medium6	GeometryHash map+1	No attempts yet	6s	1024 MB	Judgeable
Joy of Pokémon ObservationFor each habitat with total limb count t and up to three species with limb counts l_i, count the nonnegative integer solutions x_i of sum l_i x_i = t.	Medium6	Number theoryMath+1	No attempts yet	3s	2048 MB	Judgeable
DAG SerializationOrder n set and unset operations under DAG precedence so each returned result matches a register that starts false, or print -1.	Medium6	Topological sortGraph+1	No attempts yet	3s	2048 MB	Judgeable
Geometric BalanceFind the smallest positive rotation b such that rotating the turtle by b and rerunning the same commands reproduces the same ink image.	Medium6	String matchingMath+1	No attempts yet	3s	2048 MB	Judgeable
DeforestationGiven N trees on a number line and K intervals that each must keep at least t trees, find the maximum number of trees that can be cut down.	Medium6	GreedySorting+2	No attempts yet	2s	2048 MB	Judgeable
Roundabout RoundingCount integers x with 2 <= x <= N where rounding x once to the nearest power of 10 gives a different result than chain rounding through each smaller power first.	Medium6	MathImplementation	No attempts yet	2s	2048 MB	Judgeable
Grid and QueriesStarting from an N by N grid of zeros, the task applies queries that set a whole row or column to a value and prints the sum of a given row or column.	Medium6	Segment treeImplementation	No attempts yet	2s	1024 MB	Judgeable
Stock MarketGiven a periodic price sequence whose total change is negative, find the lowest price the stock reaches that is at least X, or report -1 if none exists.	Medium6	Prefix sumMath+1	No attempts yet	1s	2048 MB	Judgeable
Reporting DocumentsGiven a binary string with point flips, each query asks for the number of zero positions among x, x+k, x+2k, and so on, up to N.	Medium6	ArrayMath+1	No attempts yet	1s	2048 MB	Judgeable
Finding TreasureToggle a treasure on a cell of a line with fixed ends, then print the sum over all cells of left-gap distance times right-gap distance.	Medium6	ImplementationMath	No attempts yet	1s	2048 MB	Judgeable
Critical RoadFor each district i, count the one-way roads that every path from district 1 to district i must use in the given DAG.	Medium6	Topological sortGraph+1	No attempts yet	1s	2048 MB	Judgeable
Counting PairsCount pairs (i, j) where A_i and A_j never both have a 1 at the same even bit position (bits 0, 2, 4, ...), which is exactly when the base-2 and base-4 results match.	Medium6	Bit manipulationDynamic programming	No attempts yet	1s	2048 MB	Judgeable
Three Three ThreePlayers alternately erase the middle digit of three consecutive digits that form a multiple of 3; find the winner under optimal play.	Medium6	Game theoryMath+1	No attempts yet	1s	2048 MB	Judgeable
ICPC SquareGiven N, D, and S, find the highest floor reachable from S by moving from floor x to a multiple y of x where y minus x is at most D.	Medium6	Number theoryDynamic programming+1	No attempts yet	1s	2048 MB	Judgeable
Card GameCount the ways two players can each draw two of N numbered cards so that Vilius's sum exceeds Adomas's by exactly C.	Medium6	Hash mapSorting+1	No attempts yet	3s	2048 MB	Judgeable
Yet Another Sequence ProblemGiven the multiset of all pairwise products A_i times A_j of a length-N sequence, recover the sequence A or report NO.	Medium6	Hash mapMath+2	No attempts yet	3s	1024 MB	Judgeable
K NationsPartition a tree of cities into connected groups, each with total power at most U, minimizing the sum of squared gaps (U minus group power).	Medium6	Dynamic programmingTree	No attempts yet	1s	1024 MB	Judgeable
Mashu Vandead and the Wizard's GridDecide whether an N by N grid of nonnegative integers, where every pair of adjacent cells differs by exactly 1, can sum to K, and print one such grid if it can.	Medium6	MathMatrix+1	No attempts yet	1s	1024 MB	Judgeable
The Guardian of BalanceGiven a weighted tree, find the vertex whose distances to all vertices have the smallest variance, breaking ties by the smaller vertex number.	Medium6	TreeDynamic programming+1	No attempts yet	1.5s	1024 MB	Judgeable
AutocompleteGiven N named files with importances, answer Q prefix queries by returning the smallest index with the highest importance among matches, then add D to that file's importance.	Medium6	TrieHeap	No attempts yet	1s	1024 MB	Judgeable
PistonsGiven n pistons in cylinders of length m, each with a known position and direction, find the maximum total area they can occupy at any future moment.	Medium6	ArrayMath+1	No attempts yet	1s	2048 MB	Judgeable
Colorful IntervalsGiven n painting colors in a line, find two intervals that together contain every color, minimizing the sum of their lengths.	Medium6	Sliding windowArray+1	No attempts yet	1s	2048 MB	Judgeable