Problems

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Total results29,397 problems

Etched Emerald Orbs
Medium6
Number theory, Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Shopping Spree
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Super Lucky Palindromes
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Circles Inside a Square
Medium6
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
LIS Number
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dungeon Trouble!
Medium6
Backtracking, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
An (Almost) Perfect Match
Medium6
Dynamic programming, String matching
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Cameron's Crazy Circles
Medium6
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Camp Out
Medium6
Graph, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Square Substrings
Medium6
String, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Domino
Medium6
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cucumber
Medium6
Array, Stack+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Zapatak
Medium6
Array, Hash map+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Frizura
Medium6
Union-find, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
DeCSS 2
Medium6
Brute force, Matrix+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jelka
Medium6
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Landing Fees
Medium6
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Iksevi
Medium6
Number theory, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Suspects and Witnesses
Medium6
Graph, BFS
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Pizza Delivery
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Water Container System
Medium6
Tree, Simulation
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Story of Seasons
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Scheduling a Meeting
Medium6
Intervals, Sorting+1
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Cute Little Butterfly
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Magical Well of Lilies
Medium6
Math, Greedy
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Isomorphic?
Medium6
Graph, Tree+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Greatest common divisor
Medium6
Number theory, Math
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Fiboxor
Medium6
Math, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stacker
Medium6
Backtracking, Matrix+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Feed Store
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Demo Clean Up
Medium6
Backtracking, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lulu the Dragon Trainer
Medium6
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Highlighter Kang Minwoo
Medium6
Graph, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Camping
Medium6
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Dao's Event Planning
Medium6
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
PIN
Medium6
Math, Number theory+1
No attempts yet
Time limit
0.2s
Memory limit
1024 MB
Judgeable
Heros
Medium6
Graph, Backtracking+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Trait Growth Leap
Medium6
Math, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
A + B
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Fence Painting
Medium6
Dynamic programming, Prefix sum
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Mountain Trip
Medium6
Shortest path, BFS+2
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Candies
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Tax Collectors
Medium6
Tree, Dynamic programming
No attempts yet
Time limit
9s
Memory limit
1024 MB
Judgeable
Mopadulo
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Pop Music 2
Medium6
Greedy, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tilt tile puzzle
Medium6
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stable Sequence
Medium6
Dynamic programming, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pushpins
Medium6
Divide and conquer, Recursion+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Anti-Triangle Box
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Usuwanka (Block Removal)
Medium6
Dynamic programming, Sliding window
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Shallow Bracket Sequences
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Freight Train
Medium6
Two pointers, Binary search+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Clone Army
Medium6
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Coprime Numbers
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ballroom Dance Contest
Medium6
Tree, Implementation
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Bajtemon Collector 2
Medium6
Number theory, Math+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Way Home in Bytetown
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Cukiernia
Medium6
Greedy, Brute force
No attempts yet
Time limit
14s
Memory limit
1024 MB
Judgeable
Debt Counter
Medium6
Segment tree, Implementation
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Binary Table
Medium6
Matrix, Prefix sum
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Transfers
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mountain Ranges
Medium6
Minimum spanning tree, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Heap
Medium6
Segment tree, Array+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Discussion Club 2
Medium6
Two pointers, Sliding window+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Traveler
Medium6
Graph, Topological sort+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Transmitters
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bicycle Tour
Medium6
Union-find, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Easily Distinguishable Triangles
Medium6
Dynamic programming, Matrix
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Laser Chess
Medium6
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Train Stations
Medium6
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Book Reviewers
Medium6
Topological sort, Union-find+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Loading the Ferry
Medium6
Dynamic programming, Brute force
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Roller Coaster Queue
Medium6
Greedy, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Stolen String
Medium6
Prefix sum, Hash map+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Tunnelbana
Medium6
Tree, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Linear Congruences
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Flower Symmetry
Medium6
Greedy, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bybana
Medium6
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Baking Buns
Medium6
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Longest increasing pub-sequence
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Xorcisten
Medium6
Bit manipulation, Implementation
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Bribing Friends
Medium6
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Strongest Friendship Group
Medium6
Graph, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cellphones
Medium6
Dynamic programming, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Steady Cow Assignment
Medium6
Two pointers, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stump Removal
Medium6
Stack, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Around the World
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Space Elevator
Medium6
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Secret Milking Machine
Medium6
Graph, Binary search
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Moo University: Financial Aid
Medium6
Heap, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Navigation Nightmare
Medium6
Union-find, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Optimal Milking
Medium6
Shortest path, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jumping Cows
Medium6
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Traffic Lights
Medium6
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Nextree
Medium6
Tree, Recursion+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wooden Block Game
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cow Brainiacs
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
BUY LOW, BUY LOWER
Medium6
Dynamic programming, Hash map
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
조교의 맹연습
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Communication Stations
Medium6
Prefix sum, Geometry+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Etched Emerald OrbsGiven k, find x < y with 2/k = 1/x + 1/y and the smallest x + y, or report -1 if no such pair exists.	Medium6	Number theoryMath	No attempts yet	3s	1024 MB	Judgeable
Shopping SpreeChoose items 1 to n to maximize total value, where each chosen index k allows at most floor(k/2) chosen items among indexes 1 through k.	Medium6	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Super Lucky PalindromesGiven k, find the k-th smallest palindrome whose digits are all 4 or 7, whose digit count is lucky, and whose count of 4s or 7s is lucky.	Medium6	CombinatoricsMath+1	No attempts yet	1s	1024 MB	Judgeable
Circles Inside a SquareGiven the radius r of 8 equal circles, find the area of the smallest square that can hold them without overlap.	Medium6	GeometryMath	No attempts yet	1s	1024 MB	Judgeable
LIS NumberCount the ways to delete elements from a length-N sequence so that its LIS Number equals K, modulo 1,000,000,007.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Dungeon Trouble!Given a graph where some vertices are pre-colored with 2, 3, or 5, decide whether all vertices can be properly colored with 1 to 5.	Medium6	BacktrackingGraph	No attempts yet	1s	1024 MB	Judgeable
An (Almost) Perfect MatchFor each new track, check whether it matches any existing track after deleting at most K sections of 1 to 5 blocks, with each aligned block within tolerance T.	Medium6	Dynamic programmingString matching	No attempts yet	3s	1024 MB	Judgeable
Cameron's Crazy CirclesGiven the two legs of a right triangle, find the ratio of the total area of the infinitely many circles stacked along the longer leg to the triangle's area.	Medium6	GeometryMath	No attempts yet	1s	1024 MB	Judgeable
Camp OutDecide whether 10 students can staff a tent for all 42 four-hour shifts of the week, with 3 people per shift and at most 20 shifts each.	Medium6	GraphImplementation	No attempts yet	1s	1024 MB	Judgeable
Square SubstringsCount the substrings of S of even length 2K where each position pair (s[x], s[x+K]) is one of the N given special pairs, in either order.	Medium6	StringDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
DominoGiven a board of dominoes with one empty cell, count how many dominoes can be slid away from their original positions.	Medium6	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
CucumberCount the contiguous subarrays of a sequence whose maximum and minimum differ by an even number.	Medium6	ArrayStack+1	No attempts yet	1s	1024 MB	Judgeable
ZapatakFor each query, decide whether two equal-length subarrays can be rearranged to differ in exactly one position.	Medium6	ArrayHash map+1	No attempts yet	1.5s	1024 MB	Judgeable
FrizuraGiven current and desired strand lengths, find the fewest contiguous cuts (each at one height) that turn the current lengths into the desired ones, or -1 if impossible.	Medium6	Union-findSorting+1	No attempts yet	1s	1024 MB	Judgeable
DeCSS 2Given a partially known CSS keystream, find one 42-bit key that reproduces every known byte.	Medium6	Brute forceMatrix+1	No attempts yet	1s	1024 MB	Judgeable
JelkaGiven a binary tree and a list of node value updates, report after each update how many subtrees are binary search trees.	Medium6	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Landing FeesGiven planet fees and permits that link a planet to a range of planets, find the minimum total route cost that connects all planets.	Medium6	Minimum spanning treeUnion-find+1	No attempts yet	5s	1024 MB	Judgeable
IkseviFor each of n points, count the even diagonal lengths for which a tiling of rotated square tiles puts a tile corner on that point.	Medium6	Number theoryMath+1	No attempts yet	3s	1024 MB	Judgeable
Suspects and WitnessesGiven witness statements that name innocent guests and a cap K on stealers, count the guests who are innocent in every consistent scenario.	Medium6	GraphBFS	No attempts yet	40s	1024 MB	Judgeable
Pizza DeliveryGiven a grid with coin-changing tolls per step and pizza customers, find the maximum coins Ada can hold after M minutes if all pizzas are delivered in time.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	20s	1024 MB	Judgeable
Water Container SystemLiters are poured one at a time into containers forming a tree, and the task is to count how many containers are completely full at the end.	Medium6	TreeSimulation	No attempts yet	Not set	1024 MB	Judgeable
Story of SeasonsPlant at most X seeds per day during D warm days to maximize total sale value, where each seed must mature before winter arrives.	Medium6	GreedySorting+1	No attempts yet	Not set	1024 MB	Judgeable
Scheduling a MeetingFind the fewest scheduled meetings to cancel so that K of N Tech Leads are free for one X-hour slot within [0, D].	Medium6	IntervalsSorting+1	No attempts yet	40s	1024 MB	Judgeable
Cute Little ButterflyFind the maximum energy a butterfly can collect from flowers when it can only move down, left, or right, and each direction change costs E energy.	Medium6	Dynamic programmingSorting+1	No attempts yet	Not set	1024 MB	Judgeable
Magical Well of LiliesGiven L lilies in a well, find the minimum number of coins needed to pull all of them out using single tosses, recording tosses (4 coins), and repeat tosses (2 coins).	Medium6	MathGreedy	No attempts yet	15s	1024 MB	Judgeable
Isomorphic?Given two connected graphs, each with N vertices and N edges, decide whether they are isomorphic.	Medium6	GraphTree+2	No attempts yet	2s	1024 MB	Judgeable
Greatest common divisorGiven M and A, count the x in [1, M) that are coprime to M and satisfy Ax congruent to gcd(M, A) mod M.	Medium6	Number theoryMath	No attempts yet	8s	1024 MB	Judgeable
FiboxorFor each query (k, l, r), find the XOR of Fibonacci numbers F(l) through F(r), taken modulo 2^k.	Medium6	MathBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
StackerFind the fewest blocks of given lengths that can build a target grid of # and . cells by Tetris-style dropping, or report that it is impossible.	Medium6	BacktrackingMatrix+1	No attempts yet	1s	1024 MB	Judgeable
Feed StoreFind the shortest round trip from store A that visits farms whose total feed demand fits in the truck capacity, and print the distance and path.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	1024 MB	Judgeable
Demo Clean UpGiven a truck capacity and the weights of debris pieces on each input line, find the minimum number of truckloads needed to haul everything away.	Medium6	BacktrackingSorting	No attempts yet	1s	1024 MB	Judgeable
Lulu the Dragon TrainerOrder N dragons with distinct powers so none dominates the others by more than M at any step, or report NO.	Medium6	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Highlighter Kang MinwooPick the cheapest set of roads so every route from building A to building B has a banner, and put a banner on a road touching building K if possible.	Medium6	GraphBrute force	No attempts yet	1s	1024 MB	Judgeable
CampingFor each weather level x from 1 to M, find the campsite maximizing (B_i - kx) / (A_i + kx) and print the ratio as a reduced fraction, or 0/0 if it is 0.	Medium6	GeometrySorting+1	No attempts yet	1s	512 MB	Judgeable
Dao's Event PlanningGiven a maze whose open passages form a tree, add V visitors to every cell on each event's path during its days and print the daily totals.	Medium6	TreeDFS+1	No attempts yet	1s	512 MB	Judgeable
PINGiven n, count the triples a < b < c of distinct positive integers with sum n where, in every pair, one number is a multiple of the other.	Medium6	MathNumber theory+1	No attempts yet	0.2s	1024 MB	Judgeable
HerosGiven a DAG of n skills and m dependencies, remove up to k skills to minimize the longest chain of dependencies that remains.	Medium6	GraphBacktracking+1	No attempts yet	3s	1024 MB	Judgeable
Trait Growth LeapGiven N trait levels, each trait's item count, and M Growth Leaps, find the highest level T that every trait can reach.	Medium6	MathBinary search+1	No attempts yet	1s	1024 MB	Judgeable
A + BGiven n, count the ordered pairs of non-negative integers (a, b) whose column-wise digit sums, written out in a row, produce n.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	3s	1024 MB	Judgeable
Fence PaintingCount the ways to pick a nonempty contiguous range of segments on each of n boards so that adjacent boards' ranges overlap, modulo a prime p.	Medium6	Dynamic programmingPrefix sum	No attempts yet	6s	1024 MB	Judgeable
Mountain TripOn a grid where terrain rises to the right and downward, find the fastest time from top-left to bottom-right for k travelers and how many tie for first.	Medium6	Shortest pathBFS+2	No attempts yet	7s	1024 MB	Judgeable
CandiesCount the non-empty subsets of candy packs whose subset sums can produce every value from 1 to the subset total, modulo 1e9+7.	Medium6	Dynamic programmingSorting+1	No attempts yet	3s	1024 MB	Judgeable
Tax CollectorsFind the maximum total weight of a simple path with exactly four edges in a weighted tree of up to 200000 vertices.	Medium6	TreeDynamic programming	No attempts yet	9s	1024 MB	Judgeable
MopaduloCount the ways to split the array into contiguous blocks whose sums leave an even remainder when divided by 1000000007.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	6s	1024 MB	Judgeable
Pop Music 2Given n, find the lexicographically smallest strictly decreasing sequence of positive integers whose binary 1-bit counts sum to exactly n.	Medium6	GreedyBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Tilt tile puzzleSimulate k tilt moves on an n by m grid of empty, white, and black tiles, then print the final grid.	Medium6	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
Stable SequenceGiven N numbers up to 10^8, keep the longest subsequence whose consecutive elements share a common divisor greater than 1, and print their positions.	Medium6	Dynamic programmingNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
PushpinsGiven N and a query K, find the position of the K-th pin in the fractal layout on the segment, or print NIE if there are fewer than K pins.	Medium6	Divide and conquerRecursion+1	No attempts yet	2s	1024 MB	Judgeable
Anti-Triangle BoxCount the non-empty ways to keep sticks (by length multiplicity) so that no three kept sticks can form a triangle, with N sticks up to length M.	Medium6	Dynamic programmingSorting+1	No attempts yet	0.5s	1024 MB	Judgeable
Usuwanka (Block Removal)Each chosen block removes itself and the T_i blocks to its right. The task asks for the fewest moves needed to remove every block in the row.	Medium6	Dynamic programmingSliding window	No attempts yet	7s	1024 MB	Judgeable
Shallow Bracket SequencesGiven a correct bracket sequence and a limit H, find the fewest brackets to reverse so the sequence stays correct and its nesting depth is at most H.	Medium6	Dynamic programmingString	No attempts yet	1s	1024 MB	Judgeable
Freight TrainGiven Bitek's list as a subsequence of Bajtek's list, mark each wagon 1 if Bitek could have recorded it and 0 if he certainly missed it.	Medium6	Two pointersBinary search+1	No attempts yet	10s	1024 MB	Judgeable
Clone ArmyGiven n enemy robots, find the minimum hours to grow your army past n, where each scan costs a hours and each print costs b hours.	Medium6	GreedyMath+1	No attempts yet	1s	1024 MB	Judgeable
Coprime NumbersGiven n, k, and c, print the c integers starting at position k in the increasing list of numbers coprime to n.	Medium6	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Ballroom Dance ContestEach newcomer either adds one edge to an existing person or copies an existing person's neighbors, and queries ask a person's current degree.	Medium6	TreeImplementation	No attempts yet	10s	1024 MB	Judgeable
Bajtemon Collector 2Each card contributes either its power before or after evolution. Find the largest possible GCD of the chosen powers.	Medium6	Number theoryMath+1	No attempts yet	4s	1024 MB	Judgeable
Way Home in BytetownFind the earliest arrival at intersection n from intersection 1 using at most k bus transfers, where each bus line departs its first stop every y minutes.	Medium6	Shortest pathGraph+1	No attempts yet	3s	1024 MB	Judgeable
CukierniaGiven n display cases with counts of three pastry kinds, find the minimum number of pastries to move so every case holds one kind.	Medium6	GreedyBrute force	No attempts yet	14s	1024 MB	Judgeable
Debt CounterTwo big numbers get single-digit updates, and each query asks for one digit of their sum, with carries propagating across positions.	Medium6	Segment treeImplementation	No attempts yet	10s	1024 MB	Judgeable
Binary TableGiven a binary table and rectangle flips, report after each flip the fewest top-left rectangle flips needed to reset the table to all zeros.	Medium6	MatrixPrefix sum	No attempts yet	6s	1024 MB	Judgeable
TransfersGiven a debt matrix for N friends (N up to 16), find the fewest transfers that bring every friend's net balance to zero.	Medium6	Dynamic programmingBit manipulation	No attempts yet	1s	1024 MB	Judgeable
Mountain RangesGiven N cities and M lines that split the plane, find the minimum total number of line crossings needed to connect all cities with roads.	Medium6	Minimum spanning treeGeometry+1	No attempts yet	2s	1024 MB	Judgeable
HeapGiven an array and range-add updates, report after each update whether the array is a min-heap, where each parent is not greater than its children.	Medium6	Segment treeArray+1	No attempts yet	6s	1024 MB	Judgeable
Discussion Club 2Count the ways to split m members seated in a circle into two contiguous arcs so that every view held by someone appears in both teams.	Medium6	Two pointersSliding window+2	No attempts yet	20s	1024 MB	Judgeable
TravelerGiven a complete set of one-way roads between n cities, print for each start city the longest route that visits each city at most once.	Medium6	GraphTopological sort+1	No attempts yet	2s	1024 MB	Judgeable
TransmittersGiven a tree of chambers, find the fewest Wi-Fi transmitters so every tunnel is covered by a transmitter at an endpoint or two transmitters next to it.	Medium6	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Bicycle TourFor each junction, find the smallest largest height difference over any closed route that starts and ends there without reusing a road.	Medium6	Union-findSorting+1	No attempts yet	1s	1024 MB	Judgeable
Easily Distinguishable TrianglesCount the ways to draw a right triangle in every empty cell so that no triangle shares a side with another triangle or a black square.	Medium6	Dynamic programmingMatrix	No attempts yet	2s	1024 MB	Judgeable
Laser ChessFind the first second when smoke, spreading one cell per second, blocks every mirror-bounced laser path from the attack piece to the king.	Medium6	BFSGraph+1	No attempts yet	2s	1024 MB	Judgeable
Train StationsGiven each station's boarding and alighting counts, find an order where nobody gets off more than the people already on board, or report that no order exists.	Medium6	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
Book ReviewersAssign ratings from 1 to M to N books so that every <, =, or ≤ comparison holds, or report -1 if no assignment exists.	Medium6	Topological sortUnion-find+1	No attempts yet	6s	1024 MB	Judgeable
Loading the FerryGiven four lanes of length L and a queue of car lengths, find the largest number of cars that can board in queue order.	Medium6	Dynamic programmingBrute force	No attempts yet	6s	1024 MB	Judgeable
Roller Coaster QueueGiven a line of groups and a car that holds K people, find how many laps each group waits when later groups may board first to fill free seats.	Medium6	GreedySegment tree+1	No attempts yet	3s	1024 MB	Judgeable
Stolen StringGiven a string, find the fewest cuts so two people can each take exactly half of every letter, or report -1 if that is impossible.	Medium6	Prefix sumHash map+1	No attempts yet	5s	1024 MB	Judgeable
TunnelbanaGiven a tree subway and m trips, find the minimum total cost when one path can be covered by a card that costs k per edge.	Medium6	TreeDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Linear CongruencesGiven M and b, count pairs (a, m) with 1 <= a <= M and 2 <= m <= M where ax = b (mod m) has at least one solution.	Medium6	Number theoryMath+1	No attempts yet	1s	512 MB	Judgeable
Flower SymmetryGiven a row of N flowers with K varieties, find the fewest adjacent swaps needed to make the row symmetric.	Medium6	GreedyArray	No attempts yet	2s	1024 MB	Judgeable
BybanaFind the minimum total waste of a journey from station 1 to station N, where each trip's waste is the number of stations on its line that it skips.	Medium6	GraphShortest path	No attempts yet	1s	1024 MB	Judgeable
Baking BunsGiven N buns at distinct positions and a spatula width D, find up to 10^5 flips of length D that make the buns occupy consecutive coordinates.	Medium6	ImplementationSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Longest increasing pub-sequenceGiven N integer points, find the longest route whose consecutive Euclidean step lengths strictly increase, with no point repeated back to back.	Medium6	Dynamic programmingSorting+1	No attempts yet	3s	1024 MB	Judgeable
XorcistenAfter each point update to a list, find the smallest X that makes a_i XOR X non-decreasing, or -1 if no such X exists.	Medium6	Bit manipulationImplementation	No attempts yet	2.5s	1024 MB	Judgeable
Bribing FriendsGiven friends with popularity, bribe cost in mooney, and a cone-for-discount rate, choose who to bribe and how much to discount to maximize total popularity within A mooney and B cones.	Medium6	Dynamic programming	No attempts yet	2s	1024 MB	Judgeable
Strongest Friendship GroupFind the largest product of group size and the minimum in-group friend count over all connected groups of cows in a friendship graph.	Medium6	GraphUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
CellphonesSplit the first L letters into B contiguous button groups so the most dictionary words get unique button sequences, with ties broken by larger early buttons.	Medium6	Dynamic programmingBrute force+1	No attempts yet	1s	1024 MB	Judgeable
Steady Cow AssignmentAssign each cow to a barn within capacity so that the span of the barn rankings the cows receive is as small as possible.	Medium6	Two pointersGraph	No attempts yet	1s	1024 MB	Judgeable
Stump RemovalGiven stump heights in a line, find the fewest explosion points that destroy every stump under the strictly-shorter blast rule, and print their indices.	Medium6	StackGreedy	No attempts yet	1s	1024 MB	Judgeable
Around the WorldFind the fewest flights on a graph of farms placed on a circle that return FJ to his start after a full trip around the Earth, or report -1.	Medium6	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
Space ElevatorGiven block types with height, maximum altitude, and count, find the tallest tower where no block's top exceeds its altitude limit.	Medium6	Dynamic programmingSorting	No attempts yet	1s	1024 MB	Judgeable
Secret Milking MachineFind the smallest possible length of the longest trail Farmer John must use to make T trips from landmark 1 to landmark N without reusing any trail.	Medium6	GraphBinary search	No attempts yet	1s	1024 MB	Judgeable
Moo University: Financial AidAdmit N of C calves within a total aid budget F to find the highest possible median CSAT score of the admitted group.	Medium6	HeapGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Navigation NightmareGiven roads added one at a time on a grid map, answer the Manhattan distance between two farms using only the first I roads, or -1 if it is not yet known.	Medium6	Union-findGraph	No attempts yet	1s	1024 MB	Judgeable
Optimal MilkingAssign each of C cows to one of K milking machines, with at most M cows per machine, to minimize the longest walking distance any cow travels.	Medium6	Shortest pathBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Jumping CowsPick a subsequence of P potions so that the k-th chosen potion adds its strength when k is odd and subtracts it when k is even. Output the maximum total.	Medium6	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Traffic LightsFind the minimum time for a car to drive from position 0 to position L, starting and ending at speed 0, while obeying the traffic light cycles.	Medium6	BFSSimulation+1	No attempts yet	1s	1024 MB	Judgeable
NextreeGiven a valid code of leaf counts for a strict binary tree, print the next code in sorted order with the same leaf total, or 0 if none exists.	Medium6	TreeRecursion+1	No attempts yet	1s	1024 MB	Judgeable
Wooden Block GameMerge N numbered blocks into pouches so the median of the pouch averages is as large as possible, and print that maximum.	Medium6	Binary searchGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Cow BrainiacsGiven N up to 2,000,000 and a base B from 2 to 29, find the rightmost non-zero digit of N! written in base B.	Medium6	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
BUY LOW, BUY LOWERGiven N daily stock prices, find the length of the longest strictly decreasing buy sequence and count the distinct price sequences that reach that length.	Medium6	Dynamic programmingHash map	No attempts yet	1s	1024 MB	Judgeable
조교의 맹연습Given turn costs A, B, C and total energy K, find the fewest commands that spend exactly K and end facing the start direction, or -1 if impossible.	Medium6	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Communication StationsCount the lattice points in an N by M map that lie within Manhattan distance p_i of at least one of K stations.	Medium6	Prefix sumGeometry+1	No attempts yet	1.5s	1024 MB	Judgeable