Problems

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Total results29,442 problems

Cipher
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sea Battle
Medium5
Game theory, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Basic problem
Medium5
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Avoid the Bombs
Medium5
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
What is the value of my FIFA team?
Medium5
Heap, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pastries
Medium5
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Factory
Medium5
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Giant Jumps
Medium5
Greedy, Heap
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Table
Medium5
Greedy, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Towers
Medium5
Array, Intervals+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Archery Duel
Medium5
Game theory, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hakuna Matata Sort
Medium5
Sorting, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Escape
Medium5
Game theory, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Attack
Medium5
BFS, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Reading
Medium5
String, Probability+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cold-blooded Oak
Medium5
Tree, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stenka na stenku
Medium5
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rooted Tree
Medium5
Math, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ragnarok Day
Medium5
String matching, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Valhalla
Medium5
Simulation, Implementation
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Völund
Medium5
Greedy, Intervals+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hel
Medium5
Segment tree, Array+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Assault
Medium5
Matrix, BFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Treasures
Medium5
Sliding window, Two pointers+1
No attempts yet
Time limit
2s
Memory limit
32 MB
Judgeable
Protocol
Medium5
Implementation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Assault
Medium5
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Headmasters
Medium5
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Return
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Viruses
Medium5
Simulation, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
We Are Meat! We Are Gas!
Medium5
Array, Segment tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Metro
Medium5
Union-find, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stadium
Medium5
Combinatorics, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Palantir
Medium5
Math, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Elves vs Orcs
Medium5
Math, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pension Distribution
Medium5
Math, Probability
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Coloring
Medium5
Binary search, Implementation+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Tesseract
Medium5
String, String matching
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Garnett's House
Medium5
Matrix, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Crime Scene
Medium5
Sliding window, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crystals
Medium5
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Drawing
Medium5
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gold
Medium5
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Code Lock
Medium5
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Harry Potter and the Hall of Prophecy
Medium5
Sorting, Heap+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Squirrels
Medium5
Hash map, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Symmetric Clearing
Medium5
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bickford Fuse
Medium5
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cake
Medium5
Geometry, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Who is longer?
Medium5
String, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fibonacci Subsequence
Medium5
Hash map, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Candies
Medium5
Sorting, Two pointers+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Battle for Honey
Medium5
BFS, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Conspiracy
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bunkers
Medium5
Tree, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Interesting Numbers
Medium5
Dynamic programming, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Candies
Medium5
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Squarefree Numbers
Medium5
Math, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Mushrooms
Medium5
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Graph Game
Medium5
Graph, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Monsters
Medium5
Bit manipulation, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
SMS
Medium5
Sorting, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chessboard
Medium5
Graph, Matrix
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Flight Connection
Medium5
Sorting, Two pointers
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fragrant number
Medium5
Math, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Coincidences are random
Medium5
Implementation, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Business Meetings
Medium5
Dynamic programming, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Answer
Medium5
String, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cylon Code
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Base String
Medium5
String, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Splitting the Army into Three Squads
Medium5
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Balcony of the Castle
Medium5
Matrix, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Large Set
Medium5
Math, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fi Potion
Medium5
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Genome Palindrome
Medium5
Math, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Smooth numbers
Medium5
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Delivery
Medium5
Dynamic programming, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Reverse Grasshopper
Medium5
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Number Systems
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Healthy Diet
Medium5
Sliding window, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Beautiful Numbers
Medium5
Binary search, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sum of Powers
Medium5
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Combination Lock
Medium5
Greedy, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Convex Hull
Medium5
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fibonacci Strings 2
Medium5
Divide and conquer, Recursion+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Permutation Problem
Medium5
Combinatorics, Backtracking
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
12:30PM
Medium5
Backtracking, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lottery
Medium5
Math, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Popularity Vote
Medium5
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Namunamu, Time to Plant Trees
Medium5
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Figure Skating
Medium5
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Enigmatic Number
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sign Flip Table
Medium5
Matrix, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Trams
Medium5
Tree, DFS+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Knapsack Problem
Medium5
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Leprechaun's Gold
Medium5
Brute force, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Islands
Medium5
Graph, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Oil Mining
Medium5
Matrix, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hockey Goal
Medium5
Geometry, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Role-Playing Game
Medium5
Dynamic programming, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
How Many Stars Are in the Sky?
Medium5
Sorting, Prefix sum+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
CipherCount the original binary strings whose run-length encoding (each run's character followed by its decimal length) equals the given binary string, modulo 1e9+7.	Medium5	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
Sea BattleGiven a grid, a 1 by k ship, and one hit cell, find the fewest shots that guarantee sinking the ship in the worst case.	Medium5	Game theoryBrute force+1	No attempts yet	1s	1024 MB	Judgeable
Basic problemFor each query, compute the determinant mod 1,000,000,007 of the matrix whose entries are binomial coefficients C(a_i, j-1) for given a_1 to a_N.	Medium5	CombinatoricsMath+1	No attempts yet	1s	1024 MB	Judgeable
Avoid the BombsCount right-and-down paths from (0, 0) to (N, M) that avoid K bombs, modulo 1,000,000,007.	Medium5	CombinatoricsDynamic programming+1	No attempts yet	0.5s	1024 MB	Judgeable
What is the value of my FIFA team?Given players with positions and values, simulate K yearly rebuilds where each starter loses 1 value per year, then sum the starter values after year K.	Medium5	HeapSimulation	No attempts yet	1s	1024 MB	Judgeable
PastriesFind the maximum number of pastries Scrooge can eat within T seconds, starting at coordinate 0 on a line where each pastry at x_i takes t_i to eat.	Medium5	GreedyHeap+1	No attempts yet	2s	1024 MB	Judgeable
FactoryGiven room counts a and b, decide whether repeatedly doubling the smaller room with people from the larger one can make both rooms equal.	Medium5	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Giant JumpsGiven n jumps with lengths a_i and thresholds t_i, find the minimum total training hours over all orders of the jumps.	Medium5	GreedyHeap	No attempts yet	2s	1024 MB	Judgeable
TableFind an order of the k columns that sorts the n rows lexicographically in ascending order, or report -1 if no such order exists.	Medium5	GreedyArray	No attempts yet	2s	1024 MB	Judgeable
TowersFor each cost set, find the top and bottom tower pair with the largest total cost that no road connects, or print -1 if every pair is connected.	Medium5	ArrayIntervals+1	No attempts yet	2s	1024 MB	Judgeable
Archery DuelTwo players alternately shoot a chained target or resign, and the task is to print the first player's score under optimal play.	Medium5	Game theoryDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Hakuna Matata SortGiven a permutation of masses 1 to n, output swaps between beetles whose masses differ by at most one that sort the row in increasing order.	Medium5	SortingImplementation+1	No attempts yet	2s	1024 MB	Judgeable
EscapeSimba must cross from row 1 to row k of a k by k board while hyenas answer each move along diagonals, in an interactive format.	Medium5	Game theoryImplementation	No attempts yet	2s	1024 MB	Judgeable
AttackGiven a road network and the vampire clan in each city, decide whether the defenders of the attacked city can hold out against a werewolf army that loses min(t, a, b) per day.	Medium5	BFSSimulation+1	No attempts yet	2s	1024 MB	Judgeable
ReadingGiven a text of 10,000 to 50,000 ASCII characters, decide whether it is English fiction or random output from a generator program.	Medium5	StringProbability+1	No attempts yet	2s	1024 MB	Judgeable
Cold-blooded OakGiven a rooted tree with bulb counts on vertices, support adding and removing bulbs and answer f(x), the total wire count over all edges in the subtree of x.	Medium5	TreePrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Stenka na stenkuSplit k opponents into consecutive segments so each fighter i takes between a_i and b_i of them, or report FAIL when that is impossible.	Medium5	GreedyImplementation	No attempts yet	2s	1024 MB	Judgeable
Rooted TreeGiven N vertices, build rooted trees so that the sum of leaf depths is as large as possible, and print that maximum.	Medium5	MathGreedy	No attempts yet	2s	1024 MB	Judgeable
Ragnarok DayGiven a lowercase string, find the shortest palindrome that ends with that string by adding characters to its front.	Medium5	String matchingString	No attempts yet	2s	1024 MB	Judgeable
ValhallaChoose where each cooked portion goes on a 3-wide plate so the plate never holds more than 15 pieces, in an interactive exchange.	Medium5	SimulationImplementation	No attempts yet	5s	1024 MB	Judgeable
VölundEach day, at most m forges can be used by the smiths available that day. Find the maximum number of rings and the minimum total wage.	Medium5	GreedyIntervals+1	No attempts yet	2s	1024 MB	Judgeable
HelGiven an array with point updates, find for each range the largest pain gained by multiplying exactly one element in the range by k.	Medium5	Segment treeArray+1	No attempts yet	4s	1024 MB	Judgeable
AssaultCount the cells of an n by m grid whose pirate count is strictly greater than that of every side-adjacent cell.	Medium5	MatrixBFS	No attempts yet	2s	1024 MB	Judgeable
TreasuresGiven n piles generated by a recurrence, find the shortest consecutive block whose sum is at least the sum of all other piles.	Medium5	Sliding windowTwo pointers+1	No attempts yet	2s	32 MB	Judgeable
ProtocolGiven an n by m grid of +, -, and ?, fill each ? to maximize the largest row sum minus the smallest column sum.	Medium5	ImplementationGreedy+1	No attempts yet	2s	1024 MB	Judgeable
AssaultPick bunkers whose closing times strictly increase so the total Decepticons killed is maximized, then output the chosen bunker numbers.	Medium5	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
HeadmastersPlace N robots on positions 1 to N so that the sum of position distances over M given pairs is as small as possible.	Medium5	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
The ReturnCount the thieves who jump from a window while the firefighters, sweeping back and forth across the windows, stand under it during the thief's jump interval.	Medium5	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
VirusesGiven N cell resistances, find the smallest infectivity K that lets a virus fully capture the tissue, or report 0 if none does.	Medium5	SimulationBrute force	No attempts yet	2s	1024 MB	Judgeable
We Are Meat! We Are Gas!Count pairs of even-height players where the taller one stands left of the shorter one and at least one odd-height player stands between them.	Medium5	ArraySegment tree	No attempts yet	2s	1024 MB	Judgeable
MetroFor each train type, count the connected groups of stations linked by segments of that type, since one train covers each group.	Medium5	Union-findGraph	No attempts yet	2s	1024 MB	Judgeable
StadiumCount the seating orders of m seats where each spectator can walk to their seat from one end without passing anyone, modulo 1e9+7.	Medium5	CombinatoricsMath	No attempts yet	2s	1024 MB	Judgeable
PalantirGiven a room of size n by m, a ring of radius R starting at (x, y) with velocity (Vx, Vy), count how many times it bounces off the walls in t seconds.	Medium5	MathSimulation	No attempts yet	2s	1024 MB	Judgeable
Elves vs OrcsGiven an axis-parallel rectangle and a 45-degree rotated rectangle, determine whether they share at least one integer point.	Medium5	MathGeometry+1	No attempts yet	2s	1024 MB	Judgeable
Pension DistributionGiven the start-age distribution q among pension recipients and the age shares r, the task is to recover the ticket distribution p.	Medium5	MathProbability	No attempts yet	1s	1024 MB	Judgeable
ColoringEach step adds a rectangle anchored at (1,1), and the task is to print the area of the union of all rectangles after every step.	Medium5	Binary searchImplementation+1	No attempts yet	1.5s	1024 MB	Judgeable
TesseractCount the palindromic substrings [l, r] of a lowercase string that have some strictly larger segment which is not a palindrome.	Medium5	StringString matching	No attempts yet	2s	1024 MB	Judgeable
Garnett's HouseGiven an n by m grid with two marked cells, find the largest axis-aligned subrectangle that contains exactly one of them.	Medium5	MatrixGreedy	No attempts yet	1s	1024 MB	Judgeable
Crime SceneGiven a convex polygon with some fence sides missing, find the minimum total length of missing sides that a tape of length l walked along the boundary cannot cover.	Medium5	Sliding windowTwo pointers+2	No attempts yet	2s	1024 MB	Judgeable
CrystalsChoose a nonempty multiset of crystal types, reusing allowed, so that the sum of (a_i minus b_i) over the picks is zero, using at most 10,000 picks.	Medium5	MathGreedy+1	No attempts yet	2s	1024 MB	Judgeable
DrawingGiven a chain of segments with fixed lengths anchored at A0, decide whether its end can reach point An, and output every hinge position if so.	Medium5	GeometryMath+1	No attempts yet	2s	1024 MB	Judgeable
GoldGiven k, find the k-th smallest number a whose square ends with the same digits as a itself.	Medium5	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Code LockGiven n displays where pressing button i copies display i+1 into display i, find the fewest presses that make the sequence non-decreasing.	Medium5	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
Harry Potter and the Hall of ProphecyRepeatedly pick the closest remaining pair of 2n potions (ties go to the larger sum) and print the stronger of each pair for Neville and the weaker for Harry.	Medium5	SortingHeap+2	No attempts yet	2s	1024 MB	Judgeable
SquirrelsGiven the occupied hollow numbers in each tree, find the lowest free hollow (at least 1) in the tree each new squirrel chooses.	Medium5	Hash mapImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Symmetric ClearingGiven n trees around a circle, each birch or pine, decide whether some line through the center reflects the circle onto itself.	Medium5	StringString matching+1	No attempts yet	2s	1024 MB	Judgeable
Bickford FuseGiven a graph of knots and ropes with burn times, find the knot whose lighting lets the whole fuse burn out in the least time, and report that time.	Medium5	Shortest pathGraph	No attempts yet	2s	1024 MB	Judgeable
CakeDecide whether two perpendicular lines through the center can split the round cake into four pieces, each holding exactly one candle, with no line touching a candle.	Medium5	GeometrySorting	No attempts yet	2s	1024 MB	Judgeable
Who is longer?Given k, output the longest string over the first k lowercase letters that never has two identical adjacent pairs of characters.	Medium5	StringBrute force+1	No attempts yet	2s	1024 MB	Judgeable
Fibonacci SubsequenceDecide whether the given n numbers can be rearranged into a sequence where each term is the sum of the two before it.	Medium5	Hash mapSimulation+1	No attempts yet	2s	1024 MB	Judgeable
CandiesEach guest takes one candy from every box holding at least their boldness; output how many candies each guest eats.	Medium5	SortingTwo pointers+1	No attempts yet	2s	1024 MB	Judgeable
Battle for HoneyGiven a grid of beehives with some fences already built, find the maximum number of hives Winnie can fully enclose by placing new boards one at a time.	Medium5	BFSSimulation+1	No attempts yet	2s	1024 MB	Judgeable
ConspiracyGiven n Latin cipher words, output the index of the word whose best possible Russian decryption is lexicographically smallest.	Medium5	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
BunkersGiven a tree of n nodes, decide whether one vertex has degree 2 and its two branches are equal-sized mirror images.	Medium5	TreeHash map+1	No attempts yet	2s	1024 MB	Judgeable
Interesting NumbersCount the integers from a to b that contain at least k identical digits in a row, with b up to 4 * 10^18 and k up to 20.	Medium5	Dynamic programmingString	No attempts yet	2s	1024 MB	Judgeable
CandiesGiven integers a and b, find the fewest same-position digit swaps that make a greater than b, printing the positions or Bad luck.	Medium5	GreedyImplementation	No attempts yet	2s	1024 MB	Judgeable
Squarefree NumbersGiven k and a range [a, b] up to 10^7, find the k-th squarefree number inside that range.	Medium5	MathBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Magic MushroomsFor each of N numbers, print Yes if it is a Fibonacci number (1, 1, 2, 3, 5, ...) and No otherwise.	Medium5	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
Graph GameAlice and Bob alternately delete roads from a connected graph, and whoever disconnects it loses. Find out who loses, or print Draw.	Medium5	GraphMath	No attempts yet	2s	1024 MB	Judgeable
MonstersGiven k rooms with monster counts, decide whether powers of two (1, 2, 4, ...) can be split across rooms so each room is cleared exactly.	Medium5	Bit manipulationBrute force+1	No attempts yet	2s	1024 MB	Judgeable
SMSGiven how often each of n letters is typed and m buttons, assign the letters to buttons so the total number of presses is minimal.	Medium5	SortingDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
ChessboardGiven a black and white n by m grid, find the fewest full diagonal repaints (two diagonal directions) that turn it into a chessboard.	Medium5	GraphMatrix	No attempts yet	2s	1024 MB	Judgeable
Flight ConnectionPick the cheapest pair of flights, A to the capital and capital to B, with at least 15 minutes between landing and departure, earliest arrival in B on ties.	Medium5	SortingTwo pointers	No attempts yet	2s	1024 MB	Judgeable
Fragrant numberGiven N with up to 10^4 digits, the task is to output the N-th palindrome in increasing order, counting from 1.	Medium5	MathString+1	No attempts yet	2s	1024 MB	Judgeable
Coincidences are randomGiven contest scores, rating changes, and IP addresses, the task is to list the participants who may be violators under four stated conditions, sorted by login.	Medium5	ImplementationSimulation+1	No attempts yet	2s	1024 MB	Judgeable
Business MeetingsFind the largest set of meetings Alexei can attend in some order, given each meeting's allowed mood range and mood change, starting from mood k.	Medium5	Dynamic programmingBit manipulation	No attempts yet	2s	1024 MB	Judgeable
AnswerFind three distinct numbers from the list that, concatenated in some order, form a palindrome with no leading zeros.	Medium5	StringBrute force+1	No attempts yet	2s	1024 MB	Judgeable
Cylon CodeGiven an n by m matrix A encoded with a 2x2 matrix C (entries at most 1 in absolute value, C22 nonzero), recover the original matrix B.	Medium5	Dynamic programmingImplementation	No attempts yet	2s	1024 MB	Judgeable
Base StringGiven strings s and t, find the longest string q such that both s and t are repetitions of q, or report <<NO>> if none exists.	Medium5	StringNumber theory	No attempts yet	2s	1024 MB	Judgeable
Splitting the Army into Three SquadsCount the ways to split n warriors into three squads: a power of 3, a multiple of 13 (possibly 0), and a size in [a, b].	Medium5	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
Balcony of the CastleGiven a w by l grid with blocked cells and two start cells, decide whether the king and queen can meet directly, with one 1x3 balcony on the outer border, or not at all.	Medium5	MatrixBFS+1	No attempts yet	2s	1024 MB	Judgeable
A Large SetGiven n elements split into m classes by a function f, find the largest z that Merlin can guarantee with the k-good counting scheme, for n up to 1e18 and m up to 1e5.	Medium5	MathGreedy	No attempts yet	2s	1024 MB	Judgeable
Fi PotionCount the integers x from 2 to n where Euler's totient phi(x) divides x, which are exactly the numbers of the form 2^a times 3^b.	Medium5	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Genome PalindromeGiven n and k, find the k-th lexicographically smallest palindrome of length n over the alphabet A, C, G, T, or report that none exists.	Medium5	MathString+1	No attempts yet	2s	1024 MB	Judgeable
Smooth numbersGiven a digit count l (1 to 100), find the largest l-digit number whose interior digits are each less than the average of their neighbors, or report -1.	Medium5	MathGreedy+1	No attempts yet	2s	1024 MB	Judgeable
DeliverySplit N houses on a road between two couriers, one starting at the left end and one at the right, to minimize the total toll they pay.	Medium5	Dynamic programmingPrefix sum	No attempts yet	2s	1024 MB	Judgeable
Reverse GrasshopperGiven n blades and a target k, output which blades are intact so the grasshopper has exactly k jump paths from the first blade to the last, or report Impossible.	Medium5	Dynamic programmingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Number SystemsGiven n, b, and c, find the n-th positive integer whose base-b notation has at least one digit that is c or greater.	Medium5	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Healthy DietGiven m daily bun prices and a shelf life of k days, find the minimum cost of 2 buns per morning and how many buns to buy each day.	Medium5	Sliding windowGreedy	No attempts yet	2s	1024 MB	Judgeable
Beautiful NumbersGiven n and a set of k digits, find the n-th non-negative integer in increasing order whose leading digit is one of the chosen digits.	Medium5	Binary searchMath	No attempts yet	2s	1024 MB	Judgeable
Sum of PowersFind the n-th natural number k such that k divides 1 + 2^k + 3^k + 4^k + 5^k + 6^k, with n up to 65.	Medium5	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Combination LockGiven an n-digit number m in base k, find the smallest larger n-digit number in base k with the same digit sum, or report that none exists.	Medium5	GreedyMath	No attempts yet	2s	1024 MB	Judgeable
Convex HullGiven n integer points, count the lattice points strictly inside their convex hull, using Pick's theorem on the hull boundary and area.	Medium5	GeometryMath+1	No attempts yet	2s	1024 MB	Judgeable
Fibonacci Strings 2For each test case, count the letter a among the first k characters of the Fibonacci string F_n, where F_0 is a, F_1 is b, and F_i is F_(i-2) followed by F_(i-1).	Medium5	Divide and conquerRecursion+1	No attempts yet	2s	1024 MB	Judgeable
Permutation ProblemGiven n and k, find the k-th permutation of 1 to n in lexicographic order in which the numbers 1 and 2 are not adjacent.	Medium5	CombinatoricsBacktracking	No attempts yet	2s	1024 MB	Judgeable
12:30PMGiven segment lengths for two clocks and some time equivalences, find the segment order in each system, or report that it is ambiguous or inconsistent.	Medium5	BacktrackingBrute force+1	No attempts yet	2s	1024 MB	Judgeable
LotteryCount the integers in the range [a..b] that are divisible by exactly k of the given n numbers.	Medium5	MathHash map+1	No attempts yet	1s	1024 MB	Judgeable
Popularity VoteGiven two snapshots of vote percentages for N options, find the smallest total vote count consistent with each snapshot, with the earlier total first.	Medium5	MathNumber theory	No attempts yet	1s	512 MB	Judgeable
Namunamu, Time to Plant TreesGiven a rooted tree with fruit weights, process queries that graft a new weighted vertex onto a vertex and report the fruit weight sum on the path from a vertex to the root.	Medium5	TreeDFS+1	No attempts yet	2s	512 MB	Judgeable
Figure SkatingPick each element score c_i in [b_i, a_i] so the total is m, minimizing the entry cost where 0 is free, one-digit scores cost x, and two-digit scores cost y.	Medium5	Dynamic programming	No attempts yet	2s	1024 MB	Judgeable
Enigmatic NumberSplit the decimal string N into the fewest pieces taken from a given set of up to 1000 numbers below 1000, using each number at most once.	Medium5	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
Sign Flip TableFind a sequence of row and column sign flips so every row and column sum of an integer table is non-negative, using at most 20000 moves.	Medium5	MatrixGreedy+1	No attempts yet	2s	1024 MB	Judgeable
TramsGiven a tree and m paths between pairs of vertices, count the edges that no path passes through.	Medium5	TreeDFS+1	No attempts yet	5s	1024 MB	Judgeable
Knapsack ProblemGiven item weights and capacity c, decide whether the sets of items with total weight at most c form a matroid, printing a counterexample if not.	Medium5	MathGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Leprechaun's GoldGiven n gold pots on a line, find the fastest way to teleport once and collect them all when one pot vanishes after t minutes.	Medium5	Brute forceGreedy+1	No attempts yet	2s	1024 MB	Judgeable
IslandsGiven islands joined by bridges where each island has at most two, find the total shortest-path toll over all reachable ordered island pairs.	Medium5	GraphMath+1	No attempts yet	2s	1024 MB	Judgeable
Oil MiningFind an axis-parallel subrectangle of an n by m grid whose cell sum equals S, and print its upper-left and lower-right corners, or -1 if none exists.	Medium5	MatrixPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Hockey GoalGiven the height, width, and two depths of a hockey goal frame, find the minimum netting area needed to cover its back, sides, and top.	Medium5	GeometryMath	No attempts yet	2s	1024 MB	Judgeable
Role-Playing GamePick tasks whose prerequisites are all done, keep total time within m minutes, maximize total experience, and print one valid completion order.	Medium5	Dynamic programmingBit manipulation	No attempts yet	2s	1024 MB	Judgeable
How Many Stars Are in the Sky?Given N integer points and M axis-aligned rectangles, count the points inside or on the boundary of each rectangle.	Medium5	SortingPrefix sum+1	No attempts yet	4s	1024 MB	Judgeable