Problems

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Total results29,442 problems

Alarms
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Inflation
Medium5
Hash map, Implementation
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Peacekeeper Training
Medium5
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Biomarkers
Medium5
Greedy, String
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Lifesaving Riddle
Medium5
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
School Messages
Medium5
Implementation, Hash map
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Communication Setup
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pouring the Goo
Medium5
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mafia Game
Medium5
Brute force, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Minimal String
Medium5
String, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Electronic Lock
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Counting Operations
Medium5
Tree, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Corrupted Password
Medium5
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pitha! Pitha! Pitachu!
Medium5
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Double It
Medium5
Greedy, Heap+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sorting an Array
Medium5
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wildcard Parentheses String
Medium5
String, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
They
Medium5
Prefix sum, Two pointers+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Escape from the Abandoned House
Medium5
BFS, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sounds from the Basement
Medium5
Game theory, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chaotic Performance
Medium5
Greedy, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crazy Dominoes
Medium5
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Break Out of Encirclement
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Deadly Mathematics
Medium5
BFS, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Spell
Medium5
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Wedding
Medium5
Bit manipulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mafia Estate
Medium5
Greedy, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Artifact Transport
Medium5
Geometry, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
High-speed transport
Medium5
Math, Combinatorics
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Six-Digit Documents
Medium5
Array, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Triples
Medium5
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Ancient Runic Lock
Medium5
BFS, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crossword for a Droid
Medium5
Union-find, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Image Compression
Medium5
Math, Matrix+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Superagent Dish
Medium5
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Eating Rats
Medium5
Prefix sum, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Painting
Medium5
Segment tree, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ralph and Arithmetic
Medium5
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Coins
Medium5
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Drone Elimination
Medium5
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Castle
Medium5
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Minefield
Medium5
Array, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Optimal rearrangement
Medium5
Array, Prefix sum
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Weakening the Fleet
Medium5
Sorting, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Report
Medium5
Binary search, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Accounts
Medium5
String, Trie+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
AliKingspress
Medium5
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bad Multitasking
Medium5
Simulation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pairing Agents
Medium5
Greedy, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rick's Matrix
Medium5
Union-find, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Portal Gun
Medium5
Sorting, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Loki and Chess
Medium5
Simulation, Union-find+1
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Escape from Asgard
Medium5
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mobile Game
Medium5
Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Harmonic Series Modulo a Prime
Medium5
Number theory, Math+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Budget
Medium5
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
An Interesting Puzzle
Medium5
Minimum spanning tree, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Eastern Express Cars
Medium5
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Hard Problem
Medium5
String, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Not so rough
Medium5
Sliding window, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Waffle
Medium5
String matching, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Landscape Design
Medium5
Sorting, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hut Repair
Medium5
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Big Round Table
Medium5
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Operation Permutation
Medium5
Topological sort, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Library
Medium5
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Card Trick
Medium5
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
For Collectivism!
Medium5
Sorting, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crosswords
Medium5
Brute force, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Secret Rooms
Medium5
Graph, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Riddle of the Ancient Assassins
Medium5
Greedy, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Reuniting Gotham City
Medium5
Sorting, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Megazords
Medium5
Hash map, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Railway Crossing
Medium5
Intervals, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sweet Life
Medium5
Game theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Championship
Medium5
Greedy, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Line on the Plane
Medium5
Binary search, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Monster Ticket Booth Queue
Medium5
Simulation, Queue+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ambush
Medium5
Divide and conquer, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Surveillance by the President
Medium5
Simulation, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Minimal Period
Medium5
String, String matching
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Weapon choice
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Kevin's Swap Trap
Medium5
Sorting, Two pointers+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Kevin and the Remote Car
Medium5
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cipher Message
Medium5
Math, Binary search
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jumping on Stones
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Path to Nowhere
Medium5
Simulation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pencils
Medium5
Sorting, Sliding window
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Army Recruitment
Medium5
Segment tree, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game
Medium5
Game theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Exam
Medium5
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Domino Game
Medium5
Dynamic programming, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Graph
Medium5
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Little Mischief
Medium5
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Problem for Alf
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Favorite String
Medium5
String matching, Hash map
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gym
Medium5
Hash map, Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Bookshelf
Medium5
Math, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Physical Education Class
Medium5
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Maniac
Medium5
String, Implementation+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
AlarmsGiven three alarms and N required wake-up times, find the fewest taps needed to move one alarm per day so that each required time has a ringing alarm.	Medium5	Dynamic programmingImplementation	No attempts yet	2s	1024 MB	Judgeable
InflationGiven N dish prices, apply Q events (add x to every price, or set each price equal to x to y) and print the price sum after each event.	Medium5	Hash mapImplementation	No attempts yet	3s	1024 MB	Judgeable
Peacekeeper TrainingGiven s, find the fewest unit moves for three points starting at the origin to form a triangle with doubled area at least s.	Medium5	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
BiomarkersGiven a decimal string n, delete some digits to get the largest number divisible by 3 without leading zeros, or print 0 if none exists.	Medium5	GreedyString	No attempts yet	1s	1024 MB	Judgeable
The Lifesaving RiddleFor each shift x from 1 to n-1, decide whether some array a can produce the given difference array b under a left cyclic shift.	Medium5	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
School MessagesProcess a sequence of messenger events among school staff and students, and print how many unread messages a queried user has.	Medium5	ImplementationHash map	No attempts yet	2s	1024 MB	Judgeable
Communication SetupGiven x, y, z as floors of the geometric means of pairs from unknown positive a, b, c, the task is to find any valid a, b, c or report zeros.	Medium5	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Pouring the GooFind the fewest pours among three tanks needed to move from levels a1 to a3 into the target levels b1 to b3, or report -1 if impossible.	Medium5	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
Mafia GameGiven each night's meeting lists and the victim, find the fewest mafia members who could explain every kill, chosen among players who are never killed.	Medium5	Brute forceBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Minimal StringGiven strings a and b, repeatedly swap a character of a with a character of b to find the lexicographically smallest possible a.	Medium5	StringSorting+1	No attempts yet	2s	1024 MB	Judgeable
Electronic LockFind the largest integer without leading zeros that uses exactly n lit segments, with digits drawn only from the given set.	Medium5	Dynamic programmingGreedy	No attempts yet	2s	1024 MB	Judgeable
Counting OperationsGiven a rooted tree with integers on its vertices, find the fewest +1 or -1 root-path operations that make every vertex zero.	Medium5	TreeMath	No attempts yet	2s	1024 MB	Judgeable
Corrupted PasswordGiven strings s and t, find a position x and a character c different from s_x so that replacing s_x with c makes s a subsequence of t.	Medium5	GreedyString+1	No attempts yet	2s	1024 MB	Judgeable
Pitha! Pitha! Pitachu!Count the right triangles with a side of length sqrt(n) and at least two integer sides, printing -1 when there are infinitely many.	Medium5	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Double ItGiven N positive integers, you may double any element any number of times. Find the smallest possible gap between the maximum and minimum of the array.	Medium5	GreedyHeap+1	No attempts yet	1s	1024 MB	Judgeable
Sorting an ArrayGiven an array of up to 8 values and swap operations with costs, find the minimum total cost to sort the array, or -1 if impossible.	Medium5	Shortest pathGraph+1	No attempts yet	1s	1024 MB	Judgeable
Wildcard Parentheses StringGiven a string of '(', ')', '?', and '', decide whether the '?' and '' can be filled in to form a correct bracket string.	Medium5	StringGreedy	No attempts yet	1s	1024 MB	Judgeable
TheyGiven n points with child counts, pick a prefix ending at l and a suffix starting at r (l < r) so that the two sums differ by as little as possible.	Medium5	Prefix sumTwo pointers+1	No attempts yet	2s	1024 MB	Judgeable
Escape from the Abandoned HouseFind the smallest possible absolute temperature change over walks on a grid from s to f, where horizontal steps count -1 and vertical steps count +1.	Medium5	BFSGraph	No attempts yet	2s	1024 MB	Judgeable
Sounds from the BasementGiven a strip of R and B cells, decide whether the first player wins the game of cutting strips whose end colors differ.	Medium5	Game theoryString	No attempts yet	2s	1024 MB	Judgeable
Chaotic PerformanceGiven viewer decency levels and police intervals, lower the levels by a total of at most k to minimize the sum of each viewer's coverage times its level.	Medium5	GreedyPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Crazy DominoesGiven n, place at most n checkers on an n by n board so that the free cells have exactly one domino tiling, then print the board.	Medium5	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
Break Out of EncirclementCount the cells in an n by n grid whose Manhattan distance from cell (a, b) is exactly d, with n, a, b, and d up to 10^18.	Medium5	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Deadly MathematicsGiven two natural numbers a and b, find the fewest actions that replace one of them with its rounded geometric or quadratic mean until they are equal.	Medium5	BFSMath	No attempts yet	2s	1024 MB	Judgeable
SpellGiven big integers a and b, find the repeated digit sum of the product of all integers from a to b.	Medium5	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
WeddingAfter each arrival, departure, or XOR dance, the task is to print the total sociability of the fairies currently present.	Medium5	Bit manipulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Mafia EstateSplit the estate into n contiguous segments, each containing one son's mansion, so that the longest segment is as short as possible.	Medium5	GreedyBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Artifact TransportGiven three a_i by b_i rectangles, find the smallest area of a barge rectangle that fits all three without overlapping interiors.	Medium5	GeometryBrute force+1	No attempts yet	1s	1024 MB	Judgeable
High-speed transportCount the ways to pick new Maglev and Hyperloop ranges inside and around the old ones that keep total length and do not overlap.	Medium5	MathCombinatorics	No attempts yet	1s	1024 MB	Judgeable
Six-Digit DocumentsGiven n six-digit identifiers, find the cyclic shift that minimizes the total number of inversions summed over all six digit positions.	Medium5	ArrayPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Magic TriplesCount triples a < b < c up to n where each of the products ab, ac, and b*c is a perfect square.	Medium5	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
The Ancient Runic LockFind the shortest walk from S that touches the k stones in the given order and then reaches F, or report -1 if it is impossible.	Medium5	BFSShortest path+1	No attempts yet	2s	1024 MB	Judgeable
Crossword for a DroidFill the free cells with digits so every horizontal and vertical word is a palindrome, minimizing the total digit change from the original grid.	Medium5	Union-findSorting+1	No attempts yet	2s	1024 MB	Judgeable
Image CompressionGiven an n by m black and white grid, find the largest equal-size block tiling where each block is single-colored, then output the compressed grid.	Medium5	MathMatrix+1	No attempts yet	3s	1024 MB	Judgeable
Superagent DishGiven ingredients that can be bought, made from others, or both, find the minimum store cost to make the dish, or -1 if impossible.	Medium5	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
Eating RatsGiven a protocol of 1s and 2s that splits into two eaters with k each, find the largest lead Kratos could have over Atreus at any moment.	Medium5	Prefix sumDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
PaintingAfter each flip on a checkerboard grid, report the fewest cells to recolor so that black cells form a top block and white cells form the rest.	Medium5	Segment treePrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Ralph and ArithmeticCount the integers from 1 to n (n up to 10^18) whose decimal digits avoid every digit in a given set of minor digits.	Medium5	Dynamic programmingMath	No attempts yet	2s	1024 MB	Judgeable
CoinsFor each n, find the factor pair x and y of n^2 + 1 with both sides at least 2 and the largest perimeter, or print -1 if none exists.	Medium5	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Drone EliminationGiven n drone positions, find a shooting order so that no drone reaches the origin when drones move one step in any of 8 directions after each shot, or report -1.	Medium5	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
Magic CastleGiven a triangulation of a regular n-gon, find the minimum number of diagonals to remove so that every triangle loses at least one side.	Medium5	Dynamic programmingTree+1	No attempts yet	2s	1024 MB	Judgeable
MinefieldEvery cell starts with a mine. Process digs and find the nearest remaining mine above, below, left, or right of a given cell.	Medium5	ArrayBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Optimal rearrangementGiven a permutation, pick a value x and regroup fish into strengths below x, exactly x, and above x, keeping order within groups. Find the minimum number of inversions.	Medium5	ArrayPrefix sum	No attempts yet	4s	1024 MB	Judgeable
Weakening the FleetGiven n ship powers, output the powers in removal order, where each step removes a ship whose power equals the lower median of the remaining ships.	Medium5	SortingBinary search+1	No attempts yet	2s	1024 MB	Judgeable
ReportSplit two word lists by a vertical line on a w-wide roll so the greedy line-wrapping needs the fewest rows, then print that row count.	Medium5	Binary searchGreedy+1	No attempts yet	2s	1024 MB	Judgeable
AccountsPair 2n strings into n couples so that in each couple one string is a prefix of the other, and print the indices of each couple.	Medium5	StringTrie+1	No attempts yet	2s	1024 MB	Judgeable
AliKingspressGiven daily point values a_1 to a_n that repeat after day n, find the fewest days needed to collect exactly x points, or -1 if impossible.	Medium5	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
Bad MultitaskingEach second the first queued task runs up to b operations, then goes to the back if unfinished. Find the second when the first task (a1) finishes.	Medium5	SimulationGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Pairing AgentsSplit agents from two agencies into pairs so that the fewest agents end up with a partner that does not match their preference.	Medium5	GreedyMath	No attempts yet	2s	1024 MB	Judgeable
Rick's MatrixGiven an n by m matrix, find the fewest cells to change so that every row and every column reads the same forwards and backwards.	Medium5	Union-findMatrix+1	No attempts yet	2s	1024 MB	Judgeable
Portal GunGiven two arrays A and B of n values each, compute the sum over all index pairs (i, j) of (i - j) times \|a_i - b_j\|.	Medium5	SortingPrefix sum	No attempts yet	2s	1024 MB	Judgeable
Loki and ChessGiven a grid of pawns and q push queries, output the final board after each queried pawn pushes the chain of pawns ahead of it in the given direction.	Medium5	SimulationUnion-find+1	No attempts yet	7s	1024 MB	Judgeable
Escape from AsgardSplit groups of people between an upper deck with A seats and a lower deck with B seats, and check whether group 1 can sit on the upper deck.	Medium5	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
Mobile GameGiven red, green, and blue stone counts, decide whether repeated moves can leave all stones in a single color.	Medium5	Math	No attempts yet	2s	1024 MB	Judgeable
Harmonic Series Modulo a PrimeGiven a prime p and a range l to r, compute the sum of the modular inverses of each i in the range, modulo p.	Medium5	Number theoryMath+1	No attempts yet	4s	1024 MB	Judgeable
BudgetAssign each of n amounts as income or expense so the running balance stays within [a, b] after every operation, or report Impossible.	Medium5	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
An Interesting PuzzleGiven n integer points, split them into two non-empty sets to maximize the minimum distance across the sets, and output that distance squared.	Medium5	Minimum spanning treeGraph	No attempts yet	2s	1024 MB	Judgeable
Eastern Express CarsGiven passenger counts in n cars, find the minimum time to unload everyone when one step empties a car or removes one passenger from each nonempty car.	Medium5	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
A Hard ProblemGiven two binary sequences, find the length of the longest common subsequence that is non-decreasing.	Medium5	StringPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Not so roughGiven a lowercase string and a limit c, find the length of the longest substring with at most c pairs where an 'a' comes before a 'b'.	Medium5	Sliding windowString	No attempts yet	2s	1024 MB	Judgeable
WaffleCount the windows of length m*(a+b) in a 0/1 chocolate string that can be trimmed into a waffle with a chocolate squares, then b blank squares, repeated m times.	Medium5	String matchingPrefix sum	No attempts yet	2s	1024 MB	Judgeable
Landscape DesignGiven n column heights and a step k, find the fewest unit changes so the heights repeat every two columns and adjacent columns differ by exactly k.	Medium5	SortingGreedy	No attempts yet	2s	1024 MB	Judgeable
Hut RepairGiven an n by m sheet, find the sum over every k of floor(n/k) times floor(m/k), the most k by k squares that fit.	Medium5	MathNumber theory	No attempts yet	1s	1024 MB	Judgeable
Big Round TableMasha swaps with a neighbor on a round table of n seats exactly k times; the task is to count the seats where she can end up.	Medium5	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Operation PermutationFind the smallest number of reported pairs after which the order of soldiers is uniquely determined, or -1 if it never becomes unique.	Medium5	Topological sortGraph+1	No attempts yet	1s	1024 MB	Judgeable
LibraryGiven n books with borrow day, deadline, and reading time, decide whether one book per day can be returned on time for all of them.	Medium5	GreedyHeap+1	No attempts yet	2s	1024 MB	Judgeable
Card TrickGiven two rectangles, check whether repeatedly cutting off the largest square from each can leave two equal squares, and count the cuts.	Medium5	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
For Collectivism!Pick the largest set of assistants whose counts can all be reduced to one common value using at most k creatures in total, then list the rest.	Medium5	SortingSliding window+1	No attempts yet	2s	1024 MB	Judgeable
CrosswordsGiven 4 distinct words, count the crosswords with 2 horizontal and 2 vertical words that cross on matching letters, treating overlaid copies as one.	Medium5	Brute forceString+1	No attempts yet	2s	1024 MB	Judgeable
Secret RoomsChange the exit of one room so that starting from room 1, the exits form a single cycle through all n rooms, or report that it is impossible.	Medium5	GraphArray+1	No attempts yet	2s	1024 MB	Judgeable
The Riddle of the Ancient AssassinsGiven a string of digits, the task is to rearrange a subset of them into the largest number divisible by three, where leading zeros are allowed.	Medium5	GreedyMath+2	No attempts yet	2s	1024 MB	Judgeable
Reuniting Gotham CityGiven out-degree limits for n parts, build exactly m roads with no self-loops to maximize the largest set of parts that are all pairwise connected, or print -1.	Medium5	SortingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
MegazordsCount the ways to pick one green, one red, and one blue zord whose boundary digits match and whose three model numbers are all different.	Medium5	Hash mapMath+1	No attempts yet	2s	1024 MB	Judgeable
Railway CrossingGiven moving train segments and car arrival times, find for each car the earliest moment the crossing at x is free.	Medium5	IntervalsSorting+1	No attempts yet	2s	1024 MB	Judgeable
Sweet LifeTwo players take up to k candies per turn, never the same count as the opponent's last move; find who wins from n candies with Masya moving first.	Medium5	Game theoryMath	No attempts yet	2s	1024 MB	Judgeable
ChampionshipGiven each monster's count of acquaintances on the other team, build a bipartite acquaintance graph that meets every count, or report NO if none exists.	Medium5	GreedyGraph	No attempts yet	2s	1024 MB	Judgeable
Line on the PlaneFind the hidden integers k and b in kx+b=0 within 50 turns, where each turn adds your chosen k0 and b0 and reveals the root count and root sign.	Medium5	Binary searchMath	No attempts yet	2s	1024 MB	Judgeable
Monster Ticket Booth QueueGiven monsters that retry after k minutes when a booth holding at most m people is full, find the time each monster finishes buying its ticket.	Medium5	SimulationQueue+1	No attempts yet	2s	1024 MB	Judgeable
AmbushEach of 1000 soldiers has aimed at one of 1000 enemies, and only pairwise same-target queries are allowed; count the distinct targets within 40000 queries.	Medium5	Divide and conquerArray+1	No attempts yet	2s	1024 MB	Judgeable
Surveillance by the PresidentSimulate key presses across n text windows, where each window shows its last k characters, and find what each window holds at the end.	Medium5	SimulationString	No attempts yet	2s	1024 MB	Judgeable
Minimal PeriodGiven a string with one extra character inserted, find the shortest original block that repeats and then ends in a prefix of itself.	Medium5	StringString matching	No attempts yet	6s	1024 MB	Judgeable
Weapon choiceAssign each of n soldiers to automatic or throwing weapons to maximize total efficiency, while the two group sizes differ by at most m.	Medium5	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
Kevin's Swap TrapGiven n board weights, find two boards whose total weight is at most x and whose weights differ by at least y, or report 0.	Medium5	SortingTwo pointers+1	No attempts yet	2s	1024 MB	Judgeable
Kevin and the Remote CarGiven two digit strings, decide whether the first can be reduced to the second by repeatedly replacing adjacent digits with their sum modulo 10.	Medium5	GreedyString+1	No attempts yet	2s	1024 MB	Judgeable
Cipher MessageCount the natural numbers whose every digit lies within positions l to r of the string formed by concatenating 1, 2, 3, and so on.	Medium5	MathBinary search	No attempts yet	2s	1024 MB	Judgeable
Jumping on StonesFind the fewest 1 or 2 meter jumps from point 0 to point n that land only on stones, and print the lexicographically smallest jump sequence.	Medium5	Dynamic programmingArray+1	No attempts yet	2s	1024 MB	Judgeable
A Path to NowhereGiven an n by m grid and a start cell, count the cells visited by a spiral walk with step lengths 1, 1, 2, 2, 3, 3, and so on, until it leaves the grid.	Medium5	SimulationMath	No attempts yet	2s	1024 MB	Judgeable
PencilsPick k of n pencil sets so that the gap between the longest and shortest pencil in the combined box is as small as possible.	Medium5	SortingSliding window	No attempts yet	2s	1024 MB	Judgeable
Army RecruitmentProcess at most 366 range increments and answer range queries for the product of the values modulo 1000003.	Medium5	Segment treeImplementation	No attempts yet	2s	1024 MB	Judgeable
GameJaime and Cersei take turns subtracting 1 from a suffix of a sorted distinct array, and whoever creates a duplicate or a zero loses. Find the winner.	Medium5	Game theoryMath	No attempts yet	1s	1024 MB	Judgeable
ExamCount integers x in the range [l, r] where 10x is a perfect square and 6x is a perfect cube, with r up to 10^18.	Medium5	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Domino GameGiven n dominoes (a, b) with b at most a, find the length of the longest chain where each domino's b matches the next domino's a, without rotating.	Medium5	Dynamic programmingGraph+1	No attempts yet	2s	1024 MB	Judgeable
GraphCount non-adjacent vertex pairs where adding an edge creates exactly one simple cycle, meaning the path between them is unique.	Medium5	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
Little MischiefGiven a weighted graph as an adjacency matrix, find the largest number of vertices whose shortest distance from vertex 1 changes after removing one edge.	Medium5	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
A Problem for AlfArrange the given non-negative integers in an order so that concatenating them produces the largest possible number.	Medium5	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
Favorite StringGiven a target string s and m equal-length pieces, print the 1-based index of the piece to place at each block of s so the pieces rebuild s.	Medium5	String matchingHash map	No attempts yet	2s	1024 MB	Judgeable
GymCount the pairs of distinct points whose squared Euclidean distance equals d, given n points with integer coordinates.	Medium5	Hash mapMath	No attempts yet	3s	1024 MB	Judgeable
BookshelfFill an n by m grid with 5 colors so every 3 by 3 square has all five colors in its cross and at most four in its frame, or report -1.	Medium5	MathArray+1	No attempts yet	2s	1024 MB	Judgeable
Physical Education ClassCount the ways to split a row of n numbers into contiguous groups, each non-decreasing or non-increasing, modulo 1e9+7.	Medium5	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
ManiacGiven a substitution of the 26 letters and two strings, find how many times it must be applied to the first string to get the second, or -1 if impossible.	Medium5	StringImplementation+1	No attempts yet	Not set	1024 MB	Judgeable