Problems

Pick a problem, code in the editor, and watch the judge run real test cases. The archive is open to browse

Under construction

Still being built. Things may change

Total results29,252 problems

Magic Mine
Hard8
Binary search, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Power of Magic Spells
Hard8
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cat Goose and the Random Matrix
Hard8
Matrix, Prefix sum+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Wallet
Hard8
Prefix sum, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Defenders of Asgard
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chariot Race
Hard8
Shortest path, Dynamic programming+2
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Cipher Key
Hard8
String, String matching
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Race
Hard8
Greedy, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Worthy Finale
Hard8
DFS, Graph+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Save the Earth!
Hard8
Bit manipulation, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dipper and the Machine
Hard8
Segment tree, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Puzzle
Hard8
Matrix, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Faceted Glasses
Hard8
Geometry, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Suitcase
Hard8
Array, Sorting+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Squares and Lanterns
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Race
Hard8
Trie, String+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game
Hard8
Greedy, Heap+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Nolik and the Game
Hard8
Segment tree, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game
Hard8
Game theory, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mavis and Dracula
Hard8
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mavis at School
Hard8
Divide and conquer, Stack+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
A String Puzzle
Hard8
String, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Spells
Hard8
Dynamic programming, String matching+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Weapon Queues
Hard8
Simulation, Queue+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Light Bulb Sequence
Hard8
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jedi Queries
Hard8
Trie, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Province Capture
Hard8
Tree, Segment tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Siege of La Rochelle
Hard8
Segment tree, Shortest path+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Richelieu's Parades
Hard8
String matching, Trie+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lazybugs and the Fence
Hard8
String matching, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Air Currents
Hard8
Stack, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Routine Work
Hard8
Bit manipulation, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Homework
Hard8
Tree, Divide and conquer+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Break, Don't Build
Hard8
Graph, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
2048
Hard8
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Carpet
Hard8
String matching, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Minions having fun
Hard8
Minimum spanning tree, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lottery
Hard8
Dynamic programming, Segment tree+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Book Bag
Hard8
Sorting, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Marathon
Hard8
Shortest path, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Scar Prepares an Attack
Hard8
Dynamic programming, String+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rafiki's Test
Hard8
String, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gods
Hard8
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chino's Latte Art
Hard8
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
BlueTube Park
Hard8
Number theory, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fence
Hard8
Geometry, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Knights
Hard8
Array, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Inheritance
Hard8
Geometry, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bestin
Hard8
Union-find, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Evacuation
Hard8
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Пёсик
Hard8
Graph, DFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Ship Wheel
Hard8
Minimum spanning tree, Divide and conquer+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Harry Potter and the Railway
Hard8
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stones
Hard8
Bit manipulation, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Supersubstring
Hard8
String matching, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Circuit Design
Hard8
Graph, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Blind Flibs
Hard8
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Potions
Hard8
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Maxima
Hard8
Combinatorics, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game
Hard8
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Villa of Emblem Shape
Hard8
Geometry, Implementation
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Fair Deal of Dice
Hard8
Divide and conquer, Sorting+2
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Choreography
Hard8
Array, Simulation+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Longest Trip
Hard8
Divide and conquer, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bring Down the Sky Grading Server
Hard8
Game theory, Simulation+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Tricks of the Trade
Hard8
Prefix sum, Divide and conquer+1
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
One Hit
Hard8
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Decades of Coding Competitions
Hard8
Graph, Union-find+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Hey Google, Drive!
Hard8
Graph, BFS+1
No attempts yet
Time limit
60s
Memory limit
1024 MB
Judgeable
Love Potion
Hard8
Combinatorics, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Splitting Segments
Hard8
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Magical BF 2
Hard8
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Magical BF 3
Hard8
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Magical BF 5
Hard8
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Linesweeper
Hard8
Segment tree, Math+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Cake cutting
Hard8
Geometry, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Martian Apple Orchard
Hard8
Segment tree, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Transport Costs
Hard8
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ringteed
Hard8
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Maximum sum of GCDs
Hard8
Dynamic programming, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Logistics
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
C=A+B
Hard8
Segment tree, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Building Shortcuts
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
School Idol Project GSHS
Hard8
Dynamic programming, Stack+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Vault Robbery
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Hard Linear Algebra Problem
Hard8
Matrix, Linked list+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
MJH Script
Hard8
Matrix, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gold Digging
Hard8
Dynamic programming, Probability+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Regular Expression Edit Distance
Hard8
Dynamic programming, Recursion+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Praveen falls from a tall tree
Hard8
Tree, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Reflected Copy Tree
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Complete Mirror
Hard8
Tree, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
One Node is Gone
Hard8
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Perfect Triples
Hard8
Bit manipulation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Silver's strange exam
Hard8
Segment tree, Implementation+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Bracket Dance
Hard8
Dynamic programming, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
SNUPC Game
Hard8
Game theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
BX Bet
Hard8
Game theory, Trie+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Grow Measure Cut Repeat
Hard8
Segment tree, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Arc of Triumph 3
Hard8
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Magic MineGiven pillar heights differing by at most 1, remove exactly t meters total to maximize the lowest final height, keeping adjacent differences at most 1. Output that minimum height.	Hard8	Binary searchGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Power of Magic SpellsGiven wizard powers and up to 4 minutes with allowed ranges, choose an optional kill segment each minute to minimize the summed surviving power.	Hard8	Dynamic programmingBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Cat Goose and the Random MatrixGiven a random n by m table with entries modulo p, find the largest-sum submatrix whose sum is divisible by p.	Hard8	MatrixPrefix sum+2	No attempts yet	3s	1024 MB	Judgeable
WalletFor each bill added to a sorted wallet, find the fewest bills to pop from either end so the new bill fits in sorted order.	Hard8	Prefix sumBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Defenders of AsgardOrder each warrior's subordinates in a rooted tree (at most 7 children each) so the resulting row has the fewest inversions, and print that minimum.	Hard8	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Chariot RaceFind the minimum time for a closed route that visits the checkpoints v1 to vk in order, where each turn at an intersection takes time based on the angle.	Hard8	Shortest pathDynamic programming+2	No attempts yet	8s	1024 MB	Judgeable
Cipher KeyGiven a lowercase string s of length up to 500000, find the maximum of \|t\| + f(t)^2 over all substrings t, where f(t) is the longest proper border of t.	Hard8	StringString matching	No attempts yet	2s	1024 MB	Judgeable
RaceFor each pair u, v, find the fewest extra races needed so that v's total score beats u's, given past results and the rule that drops the s smallest scores.	Hard8	GreedyBinary search+1	No attempts yet	2s	1024 MB	Judgeable
A Worthy FinaleFind the most black pieces a single white piece can capture in one turn on a huge sparse board, changing capture direction at most twice.	Hard8	DFSGraph+1	No attempts yet	4s	1024 MB	Judgeable
Save the Earth!Find a sequence of shuttle trips that moves the leader and all superheroes to Earth without leaving a conflicting pair alone on either planet, or report -1.	Hard8	Bit manipulationBFS+1	No attempts yet	2s	1024 MB	Judgeable
Dipper and the MachineGiven range-append operations on n strings, answer substring queries on the accumulated string of a single slot.	Hard8	Segment treeBinary search+1	No attempts yet	2s	1024 MB	Judgeable
PuzzleDrop a grid figure straight onto an obstacle at a chosen horizontal shift to maximize adjacent pairs where an obstacle cell sits left of a figure cell.	Hard8	MatrixMath+1	No attempts yet	1s	1024 MB	Judgeable
Faceted GlassesFind the common water level in n glasses, each with a convex polygon base, so that the total poured volume equals v.	Hard8	GeometryBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Magic SuitcaseGiven n values, apply m swaps of equal-length segments and answer how many values in a segment lie between a and b.	Hard8	ArraySorting+2	No attempts yet	1.5s	1024 MB	Judgeable
Squares and LanternsGiven a tree where each square has a lantern range, find which squares can serve as a center where every leaf-to-center path has the same lit-lantern total while all squares meet their minimums.	Hard8	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
RacePick a subset of license plates that maximizes the count times the longest common prefix length times the longest common suffix length.	Hard8	TrieString+2	No attempts yet	2s	1024 MB	Judgeable
GameGiven N games with initial fun A_i and daily decay B_i, pick one game per day over D days to maximize the total fun of the games played.	Hard8	GreedyHeap+1	No attempts yet	8s	1024 MB	Judgeable
Nolik and the GameGiven n colored cubes with point color updates, answer each range query with the maximum number of distinct colors in any length-k window inside the query range.	Hard8	Segment treeSliding window+1	No attempts yet	2s	1024 MB	Judgeable
GameTwo players divide their own numbers A and B by a divisor up to C, keeping gcd above 1 with the other number. Print who wins.	Hard8	Game theoryNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Mavis and DraculaGiven A and B, find the largest lcm(A, x) over all integers x from 1 to B.	Hard8	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Mavis at SchoolGiven an array, find the segment whose maximum times its XOR sum is largest, and print that product.	Hard8	Divide and conquerStack+2	No attempts yet	3s	1024 MB	Judgeable
A String PuzzleFor each substring, count the pointer moves needed to take every character so the answer comes out sorted, with the pointer wrapping around the string.	Hard8	StringGreedy+2	No attempts yet	2s	1024 MB	Judgeable
SpellsFind the fewest concatenation and multiplication steps, using the given spells, that build string t, or report -1 if impossible.	Hard8	Dynamic programmingString matching+1	No attempts yet	3s	1024 MB	Judgeable
Weapon QueuesArmorers serve participants who queue at several armorers, and each query asks who is in an armorer's room at a given time, or -1 if empty.	Hard8	SimulationQueue+2	No attempts yet	3s	1024 MB	Judgeable
Light Bulb SequenceCounts the bulbs still on after k rounds, where round i flips every bulb whose number is divisible by i, with n at most 10k.	Hard8	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Jedi QueriesGiven n numbers and queries with ? wildcards, sum over every filled-in subquery how many numbers are at least that subquery.	Hard8	TrieDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
Province CaptureGiven a tree where provinces are toggled as captured, answer each path query with the number of path nodes inside the minimal subtree spanning all captured nodes.	Hard8	TreeSegment tree	No attempts yet	2s	1024 MB	Judgeable
The Siege of La RochelleTwo cycles of n rooms are linked by staircases that collapse over time; for each query, report the shortest path between rooms on opposite floors.	Hard8	Segment treeShortest path+1	No attempts yet	3s	1024 MB	Judgeable
Richelieu's ParadesFor each j, delete one length-j substring from t and find the most rows s_i whose prefix is the remaining string. Print the maximum for every j.	Hard8	String matchingTrie+1	No attempts yet	2s	1024 MB	Judgeable
Lazybugs and the FenceFor each lazybug count i, find the fewest shift commands that paint exactly the '#' boards of the fence, or report -1 if impossible.	Hard8	String matchingNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Air CurrentsRaise one air current by at most m to minimize the sum of i minus the index of the nearest strictly greater element to its left.	Hard8	StackSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
Routine WorkMove 2^n numbers through a chain of n+1 queues and n stacks so the last queue ends up holding 1 to 2^n in sorted order.	Hard8	Bit manipulationSimulation+1	No attempts yet	2s	1024 MB	Judgeable
HomeworkGiven a tree with a value on each vertex, compute the sum of (max minus min) times path length over all paths i to j.	Hard8	TreeDivide and conquer+1	No attempts yet	3s	1024 MB	Judgeable
Break, Don't BuildGiven a 2-regular geometric graph on n points, remove one incident edge per point so that the remaining edges form a non-crossing set, or report NO.	Hard8	GraphGeometry+1	No attempts yet	2s	1024 MB	Judgeable
2048Count the 16-color h by w grids where no two side-adjacent cells share a color, modulo 1,000,000,007, for h up to 6 and w up to 10^18.	Hard8	Dynamic programmingMatrix+1	No attempts yet	2s	1024 MB	Judgeable
CarpetCount substrings s[i..j] that split into a piece occurring entirely left of i and a piece occurring entirely right of j, joined in order.	Hard8	String matchingDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable
Minions having funGiven a weighted multigraph, find a closed route that uses each edge at most once and maximizes the sum of its minimum and maximum edge weights.	Hard8	Minimum spanning treeGraph	No attempts yet	2s	1024 MB	Judgeable
LotteryCount arrays of n integers in [1, k] where each given range maximum query returns its specified value, modulo 1e9+7.	Hard8	Dynamic programmingSegment tree+2	No attempts yet	2s	1024 MB	Judgeable
Book BagPick K books to minimize the total weight plus the largest volume plus the smallest thickness among them, and print the chosen book numbers.	Hard8	SortingSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
MarathonFor each student j from 1 to K, find the shortest walk from checkpoint 1 to N that visits exactly j checkpoints, then sum the lengths modulo 998244353.	Hard8	Shortest pathDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Scar Prepares an AttackCount the ways to pick a nonempty subsequence of each hyena's genotype so that each chosen birth genotype is stronger than the next, modulo 1e9+7.	Hard8	Dynamic programmingString+2	No attempts yet	2s	1024 MB	Judgeable
Rafiki's TestFind the base x and modulus p of a polynomial string hash by querying the hash of chosen strings in an interactive session.	Hard8	StringMath+2	No attempts yet	2s	1024 MB	Judgeable
GodsSplit n gods into two lines so that no quarreling pair shares a line and no two attack segments cross, or print -1 if impossible.	Hard8	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
Chino's Latte ArtConstruct a simple polygon with exactly 100000 vertices that is heart-shaped, symmetric about line AB, with coordinates within 2,000,000 in absolute value.	Hard8	GeometryImplementation+1	No attempts yet	1s	1024 MB	Judgeable
BlueTube ParkFor each A_i, find the smallest index j (j not equal to i) whose value is closest in prime-operation distance, where each multiply or divide by a prime counts as one step.	Hard8	Number theoryHash map+1	No attempts yet	2s	1024 MB	Judgeable
FenceGiven a convex polygon and one interior post, find a maximum-area polygon whose vertices are these posts, with no other post strictly inside it.	Hard8	GeometryDynamic programming	No attempts yet	2s	1024 MB	Judgeable
KnightsGiven n knights in a line and m position swaps, count pairs where the shorter knight stands in front, modulo 1e9+7, with n up to 1e18.	Hard8	ArrayImplementation+1	No attempts yet	2s	1024 MB	Judgeable
InheritanceSplit n watchtowers into two convex polygons with disjoint hulls so that the difference of their areas is minimal, or report -1 if impossible.	Hard8	GeometryBrute force	No attempts yet	2s	1024 MB	Judgeable
BestinAfter each torn-down wall, count the sub-rectangles that are sealed off by walls on the perimeter and open inside.	Hard8	Union-findHash map+1	No attempts yet	2s	1024 MB	Judgeable
EvacuationFind the minimum time to send K cars from city 1 to city n over timed, capacitated one-way roads, or the fewest cars that miss the deadline T.	Hard8	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
ПёсикGiven a connected graph with at most three simple cycles, find the longest simple cycle and print its vertex numbers in order.	Hard8	GraphDFS+1	No attempts yet	3s	1024 MB	Judgeable
Ship WheelGiven a wheel graph with n rim joints and 2n weighted sticks, find the minimum spanning tree cost before and after each of q edge cost updates.	Hard8	Minimum spanning treeDivide and conquer+2	No attempts yet	5s	1024 MB	Judgeable
Harry Potter and the RailwayAssign each railway a distinct spell number from 1 to m so that every station's incident spell numbers have gcd 1, or report IMPOSSIBLE.	Hard8	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
StonesCount the sets of distinct stone segments, each with binary value at most k, whose flips turn an all-white row into the binary number n, modulo 1e9+7.	Hard8	Bit manipulationDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
SupersubstringGiven a text t and many queries s, split each s into the fewest pieces that are substrings of t and print them joined by \|, or NO if impossible.	Hard8	String matchingGreedy	No attempts yet	2s	1024 MB	Judgeable
Circuit DesignGiven a DAG logic circuit of and, or, and not gates with input changes that may arrive at different times, decide whether each output can glitch.	Hard8	GraphSimulation	No attempts yet	2s	1024 MB	Judgeable
Blind FlibsGiven a binary word w, find for each k from 1 to \|w\| the maximum predictive power of a k-state blind automaton that predicts the endlessly repeated string w*.	Hard8	StringString matching+1	No attempts yet	2s	1024 MB	Judgeable
Magic PotionsGiven n substances with a bottles each, pick pairs of different substances to make the most potions, breaking ties by favoring 1+2, then 1+3, 1+4, and so on.	Hard8	GreedyMath+1	No attempts yet	2s	1024 MB	Judgeable
MaximaCount permutations of 1 to n with exactly k maxima, where n is up to 10^15 and the answer is taken modulo 239.	Hard8	CombinatoricsMatrix+1	No attempts yet	2s	1024 MB	Judgeable
GameGiven a road network where a road of length c holds c-1 villages, decide which of two alternating players reaches the capital first.	Hard8	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
Villa of Emblem ShapeGiven a simple polygon, decide whether translated copies of it (no rotation or reflection) can be overlaid to form a convex polygon.	Hard8	GeometryImplementation	No attempts yet	8s	1024 MB	Judgeable
Fair Deal of DiceGiven dice with custom face values, pick m of n dice and split them between two players to minimize the expected squared difference of their face sums.	Hard8	Divide and conquerSorting+2	No attempts yet	8s	1024 MB	Judgeable
ChoreographyApply cyclic shifts, pair swaps, and permutation moves to a line of dancers, then report where a given dancer stands after each prefix of moves.	Hard8	ArraySimulation+1	No attempts yet	0.5s	1024 MB	Judgeable
Longest TripFind a longest simple path in a hidden graph by asking whether any road exists between two disjoint sets of landmarks.	Hard8	Divide and conquerGraph+1	No attempts yet	1s	1024 MB	Judgeable
Bring Down the Sky Grading ServerFor each scenario, decide whether the hacker can drop the server's computing power to 0 or below when the chairman plays optimally.	Hard8	Game theorySimulation+1	No attempts yet	4s	1024 MB	Judgeable
Tricks of the TradeBuy a segment of at least K robots, sell exactly K of them, and find the maximum profit along with every robot that can be sold in an optimal deal.	Hard8	Prefix sumDivide and conquer+1	No attempts yet	7s	1024 MB	Judgeable
One HitEach skill maps attack x to a*x+b, and the task asks for the fewest skill uses that take starting attack x to at least boss HP y, or -1.	Hard8	GreedyMath+1	No attempts yet	2s	1024 MB	Judgeable
The Decades of Coding CompetitionsGiven bus routes each tagged with a club, count the contests (P, C) for which some walk between the two stops touches an odd number of distinct clubs.	Hard8	GraphUnion-find+1	No attempts yet	Not set	1024 MB	Judgeable
Hey Google, Drive!Given a grid of walls and hazards, list each start and finish pair the car can reach with probability near 1 despite random command swaps.	Hard8	GraphBFS+1	No attempts yet	60s	1024 MB	Judgeable
Love PotionGiven K, count the subsets of cards numbered 1 to 2023K whose sum is coprime with 2023, modulo 10^9+7.	Hard8	CombinatoricsNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Splitting SegmentsGiven N segments, find the shortest [A, B] that covers at least half of every segment after exactly K splits, where each split cuts a segment in two.	Hard8	Binary searchGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Magical BF 2Write an N by N BF grid that leaves x mod 7 in cell M0 for input x up to 200, whether the grid is read by rows or by columns.	Hard8	ImplementationMath	No attempts yet	1s	1024 MB	Judgeable
Magical BF 3Write an N by N grid of BF code that stores the index of the leftmost zero cell in M0, correct when the grid is read by rows and by columns.	Hard8	ImplementationSimulation	No attempts yet	1s	1024 MB	Judgeable
Magical BF 5Write an N by N Brainfuck grid that, read by rows and by columns, stores the maximum of the input cells (at most 100 values, each at most 50) in M0.	Hard8	ImplementationSimulation	No attempts yet	1s	1024 MB	Judgeable
LinesweeperAfter each single-cell change to the top row, the task is to say whether a given bottom cell must hold a mine, must be empty, is undetermined, or the top row has no valid bottom row.	Hard8	Segment treeMath+1	No attempts yet	4s	1024 MB	Judgeable
Cake cuttingGiven an M by N cake cut into unit squares, plus slanted cuts that form squares of area S at slope Q/P, count the resulting pieces.	Hard8	GeometryNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Martian Apple OrchardApples on a row of trees ripen when every apple of a given ripeness moves up by one; count trees in a range whose ripeness is at most Y.	Hard8	Segment treeHash map+1	No attempts yet	2s	1024 MB	Judgeable
Transport CostsGiven a tree of N cities and K marked cities, find the contest city minimizing the sum of squared distances to the marked cities.	Hard8	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
RingteedCount the squares where a simple walk starting at square S can end in a connected graph whose cycles share no vertices.	Hard8	GraphDFS+1	No attempts yet	1s	1024 MB	Judgeable
Maximum sum of GCDsSplit a fixed sequence of pile sizes into contiguous shelves of at least D piles each (or empty) to maximize the sum of each shelf's GCD.	Hard8	Dynamic programmingNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
LogisticsFor each store, count the valid production sequences from factory 1 that end at the store's factory with a level in its range, modulo 1e9+7.	Hard8	TreeDynamic programming+1	No attempts yet	15s	1024 MB	Judgeable
C=A+BProcess range adds, updates that set each C-painted element to the sum of its matching A and B elements, and range sum queries on a sequence colored A, B, or C.	Hard8	Segment treeArray+1	No attempts yet	2s	1024 MB	Judgeable
Building ShortcutsGiven a weighted road network with central villages, find the maximum number of new shortcuts between non-adjacent villages that keep each village's nearest center and distance unchanged.	Hard8	GraphShortest path+2	No attempts yet	3s	1024 MB	Judgeable
School Idol Project GSHSSplit N students into consecutive groups of at most M students so that the sum of (max minus min) over all groups is maximized, and print one optimal split.	Hard8	Dynamic programmingStack+1	No attempts yet	1s	1024 MB	Judgeable
Vault RobberyFind the maximum loot on a route that ends at building E, moving only to visible buildings and never robbing two consecutive visited buildings, as values and E change over Q updates.	Hard8	TreeDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
Hard Linear Algebra ProblemGiven two invertible matrices A and B over a prime field, count the columns i where swapping column i between them keeps both invertible, for each cyclic shift of A.	Hard8	MatrixLinked list+1	No attempts yet	1s	1024 MB	Judgeable
MJH ScriptRun a 26-variable MJH program with GOTO jumps, stopping after P jumps, then print selected PRINT values and the final variables modulo 1,000,000,007.	Hard8	MatrixSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Gold DiggingGiven pits with a breakdown chance, an extraction rate, and gold amounts, find the best expected gold when one machine is assigned to one pit per day.	Hard8	Dynamic programmingProbability+1	No attempts yet	4s	1024 MB	Judgeable
Regular Expression Edit DistanceGiven two regular expressions over a and b, find the minimum edit distance between any string matched by the first and any string matched by the second.	Hard8	Dynamic programmingRecursion+1	No attempts yet	5s	1024 MB	Judgeable
Praveen falls from a tall treeEach tree node gets a peeling layer value S, and each query asks for the number of inversion pairs in S along the path between two nodes.	Hard8	TreeDivide and conquer+1	No attempts yet	1s	1024 MB	Judgeable
Reflected Copy TreeGiven a tree with N nodes, reflected-copy it K times and print the sum of all pairwise distances modulo 10^9+7.	Hard8	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Complete MirrorFind a root in a tree so that all vertices at the same depth have the same degree, or report -1 if no such root exists.	Hard8	TreeBFS+1	No attempts yet	1s	1024 MB	Judgeable
One Node is GoneGiven a tree with 2^n - 2 vertices, find every parent vertex from which removing one non-root vertex yields a perfect binary tree of size 2^n - 1.	Hard8	TreeDFS+2	No attempts yet	1s	1024 MB	Judgeable
Perfect TriplesGiven n up to 1e16, find the n-th element of a sequence built by repeatedly appending the lexicographically smallest unused triple with XOR zero.	Hard8	Bit manipulationMath	No attempts yet	2s	1024 MB	Judgeable
Silver's strange examStudents enter and leave a lab holding integers, and each strange event awards points to students with unique values; print each entrant's final score.	Hard8	Segment treeImplementation+1	No attempts yet	3s	1024 MB	Judgeable
Bracket DancePick 2K brackets from the string, keeping their order, so they form a correct bracket sequence with the largest total beauty, for each K from 1 to N/2.	Hard8	Dynamic programmingGreedy+1	No attempts yet	3s	1024 MB	Judgeable
SNUPC GameGiven token counts on five cells with forward moves and a U-to-S loop, decide if the first player wins, loses, or the game never ends.	Hard8	Game theoryMath	No attempts yet	1s	1024 MB	Judgeable
BX BetTwo players alternately add a chosen earlier opponent number to their own, digit-wise mod 10, and the task is to find the winner from both notebooks.	Hard8	Game theoryTrie+1	No attempts yet	2s	1024 MB	Judgeable
Grow Measure Cut RepeatProcess a sequence of tent-shaped watering updates, height caps, and point queries on 100000 trees, printing each measured height.	Hard8	Segment treeImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Arc of Triumph 3Output a stable build order for a stone arc cross-section, placing and removing wooden blocks so that the fewest wooden blocks are used.	Hard8	SimulationGreedy+1	No attempts yet	1s	1024 MB	Judgeable