Problems

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Total results29,413 problems

Sherlock Holmes
Medium6
Brute force, Number theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
ДВА НИЗА
Medium6
String, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
МАГАЗИН
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rectangles
Medium6
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Counting substrings
Medium6
Backtracking, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Art calendar
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Digit Sequence
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lazy Haegang
Medium6
Graph, Union-find+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
123456789 Points
Medium6
Math, Binary search+2
No attempts yet
Time limit
0.2s
Memory limit
512 MB
Judgeable
Myeongjin's New Year Plan
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Say xor NO!
Medium6
Trie, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
ilove Strings
Medium6
String, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stacking Up
Medium6
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Algorithm Class - Matrix Path Problem 3
Medium6
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Matrix Path Problem 6
Medium6
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Matrix Path Problem 7
Medium6
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Card Game
Medium6
Brute force, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Eating Candy Evenly
Medium6
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Password
Medium6
Implementation, Binary search
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Barista Power
Medium6
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Land Division
Medium6
Prefix sum, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
I Want to Receive at Least a Special Prize
Medium6
Divide and conquer, Recursion+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Intercastellar
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
blobnom
Medium6
Array, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bottleneck Travelling Salesman Problem (Small)
Medium6
Graph, Brute force+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Zombie Virus
Medium6
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Beautiful String
Medium6
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
SKK String
Medium6
Prefix sum, Hash map+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Strange Galton Board
Medium6
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Beautiful Sequence
Medium6
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hacking
Medium6
Graph, Topological sort
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Road Information
Medium6
Prefix sum, Hash map+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Too Much Work...
Medium6
Number theory, Combinatorics+1
No attempts yet
Time limit
1.111s
Memory limit
1111 MB
Judgeable
Correct Parentheses
Medium6
String, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ball of Whacks
Medium6
Geometry, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Growing Some Oobleck
Medium6
Simulation, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pinned Files
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Square Pool
Medium6
Binary search, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Good Samples
Medium6
Sliding window, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Concert Rehearsal
Medium6
Binary search, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lone Rook
Medium6
BFS, Graph+1
No attempts yet
Time limit
11s
Memory limit
1024 MB
Judgeable
Reversibly Cyclic Strings
Medium6
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Diagonals
Medium6
Backtracking, Graph+2
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Fail Them All!
Medium6
Graph, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Square Bounce
Medium6
Math, Geometry+2
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Moo Network
Medium6
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Sleeping in Class
Medium6
Array, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crypto Market Analysis
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Degrees, radians, gradians
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Chess Knight
Medium6
Implementation, Binary search+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Centennial Woodpecker
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fallen Server
Medium6
Greedy, Matrix+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Day Streak
Medium6
Two pointers, Sorting+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Gifting a Sequence
Medium6
Array, Binary search+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Billboard Announcements
Medium6
Intervals, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Build The Grid
Medium6
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Coins and Boxes
Medium6
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Edges, Colors and MST
Medium6
Topological sort, Tree+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hidden Rook
Medium6
Binary search, Math
No attempts yet
Time limit
15s
Memory limit
256 MB
Judgeable
Stone Piles Game 2
Medium6
Game theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Expression Completion Game
Medium6
Game theory, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Attack Order
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Diameter Two
Medium6
Graph, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Implemented Incorrectly
Medium6
Combinatorics, Simulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Even Forest
Medium6
Tree, DFS+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Survey
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Tri-Color Puzzle
Medium6
Math, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Checker Slide
Medium6
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
How Many Unicycles in a Broken Wheel
Medium6
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Neighbors
Medium6
Backtracking, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Antialiasing
Medium6
Geometry, Implementation+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Team Change
Medium6
Graph, BFS
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Cracker Barrel Game
Medium6
Backtracking, Brute force+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Substitution Mania!
Medium6
Brute force, Hash map+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Shortest and Longest LIS
Medium6
Greedy, Array+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
1-Trees and Queries
Medium6
Tree, DFS+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Animal Observation (easy version)
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Palindrome Free Strings
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Interesting Integers
Medium6
Dynamic programming, Math
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Moving Cells
Medium6
Dynamic programming, Sliding window
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Army of Clones
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Race
Medium6
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Railroad sorting
Medium6
Stack, Simulation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Table Split
Medium6
Math, Binary search+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Mutated DNA
Medium6
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Jumping Robot
Medium6
Array, Sliding window
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
New Year at the Kindergarten
Medium6
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gifts
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Maximum Rest
Medium6
Binary search, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Traffic Volume Survey
Medium6
Graph, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Find the Hyper Spot to Lie Down In
Medium6
Hash map, Sorting+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Vote Counting
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Center Stage
Medium6
Segment tree, Array
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cubic Cycle
Medium6
Backtracking, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Similar Spacing
Medium6
Dynamic programming, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Cross Covers Everything
Medium6
Sorting, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Balanced numbers
Medium6
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Photoshoot
Medium6
Greedy, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Because, Art!
Medium6
Sorting, Greedy
No attempts yet
Time limit
0.3s
Memory limit
1024 MB
Judgeable
Expedition Plans
Medium6
Dynamic programming, Intervals
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Sherlock HolmesFor each month, count five-digit numbers formed by N1 = month + 10, the digit s, and a valid N3 <= N, where the concatenation is divisible by the sum of some two of the three volumes; also output the triple with smallest N3 for the given month.	Medium6	Brute forceNumber theory+2	No attempts yet	1s	1024 MB	Judgeable
ДВА НИЗАGiven two digit strings, find the largest difference between any cyclic shift of the first read as a number and any cyclic shift of the second, where shifts starting with 0 are excluded.	Medium6	StringGreedy+2	No attempts yet	1s	1024 MB	Judgeable
МАГАЗИНSplit the given item prices across receipts so that on each receipt the floor(size/k) cheapest items are free, minimizing the total paid.	Medium6	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
RectanglesGiven three rectangles, the program must arrange them without overlap into one rectangle of the same total area and print the layout as a dot diagram.	Medium6	GeometryImplementation	No attempts yet	1s	1024 MB	Judgeable
Counting substringsCount the distinct strings that can be built from some subset of the distinct letters of S and that contain P as a contiguous substring.	Medium6	BacktrackingCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Art calendarGiven a year, the weekday of 1 January, and a date (or the word Flip), report the date(s) printed on the face and back of the corresponding calendar sheet.	Medium6	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Digit SequencePowers of x (1, x, x^2, ...) are concatenated with no separators; find the n-th digit of the resulting string.	Medium6	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Lazy HaegangGiven a graph of connected buildings and a schedule of N courses, count the minimum number of times the walk between consecutive classes must leave the connected-component structure, i.e. go outside.	Medium6	GraphUnion-find+2	No attempts yet	0.5s	512 MB	Judgeable
123456789 PointsGiven N notes and a target score S, find counts of Perfect, Great, Good judgments giving exactly S, or report -1.	Medium6	MathBinary search+2	No attempts yet	0.2s	512 MB	Judgeable
Myeongjin's New Year PlanEach illness is a (red, blue, danger) triple; for each student's pill pair find the maximum danger sum achievable by a subset of illnesses with exactly those pill counts, then sort students by risk then number.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	512 MB	Judgeable
Say xor NO!Count the pairs of numbers from two lists whose bitwise XOR is smaller than K.	Medium6	TrieBit manipulation	No attempts yet	1s	1024 MB	Judgeable
ilove StringsCount length-5 subsequences that alternate vowel-consonant starting with a vowel and have distinct characters, modulo 1e9+7.	Medium6	StringDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Stacking UpGiven a target stack of positive integers, output a program using only 1, d, and + that builds it from an empty stack, where + also decrements the remaining entries.	Medium6	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Algorithm Class - Matrix Path Problem 3Given an n by n grid of positive integers, find the maximum right/down path score from (1,1) to (n,n) that passes through a given cell, and the maximum that avoids it.	Medium6	Dynamic programmingMatrix+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Matrix Path Problem 6Given an n x n grid of positive integers and a set of P cells, find the maximum sum along a right/down path from (1,1) to (n,n) that visits every listed cell, or -1 if impossible.	Medium6	Dynamic programmingMatrix+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Matrix Path Problem 7Given an n by n grid of 1s and 2s and a set of marked cells, find the maximum-sum right/down path from top-left to bottom-right, and among such paths the one visiting the most marked cells.	Medium6	Dynamic programmingMatrix+2	No attempts yet	1s	512 MB	Judgeable
Card GameGiven Bob's row of digits and Alice's digits, find the largest number Alice can form (using at least one card) that is smaller than both readings of Bob's row.	Medium6	Brute forceGreedy+2	No attempts yet	1s	512 MB	Judgeable
Eating Candy EvenlyArrange candies so no two adjacent pieces share a kind, choose the lexicographically smallest order, and output the sum of i times Z[i] modulo 987654323.	Medium6	GreedyMath	No attempts yet	1s	512 MB	Judgeable
PasswordRecover an N-letter password over the first S lowercase letters, using queries that return the length of the longest prefix of a guess that is a subsequence of the password.	Medium6	ImplementationBinary search	No attempts yet	3s	1024 MB	Judgeable
Barista PowerIn a grid maze, find the shortest path from the top-left to the bottom-right, where you may clear all walls along one straight row or column direction at most once.	Medium6	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Land DivisionCount the ways to cut the grid with vertical and horizontal lines so that every resulting region has the same total population.	Medium6	Prefix sumImplementation+2	No attempts yet	1s	1024 MB	Judgeable
I Want to Receive at Least a Special PrizeGiven an N x N grid of distinct numbers (N a power of two), recursively pick the second smallest survivor of each quadrant and output the final number.	Medium6	Divide and conquerRecursion+2	No attempts yet	1s	512 MB	Judgeable
IntercastellarEach even piece is repeatedly halved, always choosing the rightmost even piece, and queries ask for the final length at given positions from the left.	Medium6	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
blobnomEach operation takes one blob from both neighbors of a middle tower and stacks it on that tower; find the greatest height any tower can reach.	Medium6	ArrayGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Bottleneck Travelling Salesman Problem (Small)Given a small directed weighted graph, find a Hamiltonian cycle minimizing the largest edge cost on the cycle, and output that cost plus one optimal tour.	Medium6	GraphBrute force+2	No attempts yet	1s	1024 MB	Judgeable
Zombie VirusTwo viruses spread one cell per hour from fixed sources on a grid; when both reach a cell within the same hour, virus 3 forms there. Count final cells of each type.	Medium6	BFSGraph+2	No attempts yet	2s	1024 MB	Judgeable
Beautiful StringGiven string S and a string T with all distinct characters, find how many disjoint copies of T can be extracted from S, each copy preserving S order.	Medium6	GreedyString+2	No attempts yet	1s	1024 MB	Judgeable
SKK StringFind the longest substring where the count of K equals twice the count of S, with both letters present, or report -1.	Medium6	Prefix sumHash map+2	No attempts yet	1s	1024 MB	Judgeable
The Strange Galton BoardA Galton board where a marble from each starting peg lands uniformly on its reachable bottom slots. Process drop queries, then answer range-sum expectation queries on the destination line.	Medium6	MathCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Beautiful SequenceGiven a sequence and exactly K adjacent swaps, find the lexicographically smallest sequence that can be reached.	Medium6	GreedyArray	No attempts yet	1s	1024 MB	Judgeable
HackingGiven N rooms where each room points to one next room, find the most distinct rooms a walk can visit after changing one room's next pointer.	Medium6	GraphTopological sort	No attempts yet	2s	512 MB	Judgeable
Road InformationCount contiguous substrings of a string over T, G, F, P in which every character occurs a number of times divisible by 3.	Medium6	Prefix sumHash map+2	No attempts yet	1s	1024 MB	Judgeable
Too Much Work...Count integers from 1 to N that have a divisor made of two or more repeated 1 digits (11, 111, 1111, and so on), with N up to 10^18.	Medium6	Number theoryCombinatorics+1	No attempts yet	1.111s	1111 MB	Judgeable
Correct ParenthesesCount how many single-character deletions from a bracket string leave a correct balanced parenthesis sequence.	Medium6	StringPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Ball of WhacksGiven three sections of a 30-piece polyhedron, decide whether they can be moved and joined into one complete ball.	Medium6	GeometryBacktracking+1	No attempts yet	1s	1024 MB	Judgeable
Growing Some OobleckGiven circles that grow at fixed rates, find the center and radius of the single circle formed after all touching circles merge in chain reactions.	Medium6	SimulationGeometry+1	No attempts yet	1s	1024 MB	Judgeable
Pinned FilesGiven a start and target ordering of pinned and unpinned files, find the minimum number of pin/unpin toggles that transforms one into the other.	Medium6	Dynamic programmingArray+2	No attempts yet	1s	1024 MB	Judgeable
Square PoolGiven an N by N yard with T tree cells, find the side length of the largest axis-aligned square that contains no tree.	Medium6	Binary searchPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Good SamplesGiven N, M, and K, build a sequence of N pitches in 1 to M with exactly K subarrays that have no repeated values, or report -1.	Medium6	Sliding windowMath+2	No attempts yet	1s	1024 MB	Judgeable
Concert RehearsalGiven n performance durations that repeat in a fixed cycle, count how many complete cycles fit into k days where each day holds performances up to duration p.	Medium6	Binary searchPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Lone RookGiven a board with one rook, knights, and a target, decide whether the rook can reach the target by stopping only on squares no knight attacks.	Medium6	BFSGraph+1	No attempts yet	11s	1024 MB	Judgeable
Reversibly Cyclic StringsDecide whether every proper substring of s has its reverse appearing as a substring of some rotation of s, for \|s\| up to 1000.	Medium6	StringString matching+2	No attempts yet	1s	1024 MB	Judgeable
DiagonalsFill an n by n grid with diagonals so that given intersection counts match and no cycle of diagonals forms.	Medium6	BacktrackingGraph+2	No attempts yet	8s	1024 MB	Judgeable
Fail Them All!Given each student's partial True/False answers, find the lexicographically smallest answer key so that every student has at most one correct answer, or report -1.	Medium6	GraphGreedy	No attempts yet	2s	1024 MB	Judgeable
Square BounceA ray starts at (-1,0) inside a unit square, bounces n times off the sides at equal angles, and you report the rational coordinates of the n-th hit point in lowest terms.	Medium6	MathGeometry+2	No attempts yet	7s	1024 MB	Judgeable
Moo NetworkGiven N cows at integer points (x, y) with y from 0 to 10, find the minimum total squared-distance cost to connect all cows into one network.	Medium6	Minimum spanning treeUnion-find+2	No attempts yet	4s	1024 MB	Judgeable
Sleeping in ClassCombine adjacent entries of an array so all resulting values are equal, using the fewest merges.	Medium6	ArrayPrefix sum+2	No attempts yet	2s	1024 MB	Judgeable
Crypto Market AnalysisGiven three daily multipliers a1, a2, a3, find the first day t >= 1 when a1^t + a2^t equals a3^t, or report that it never happens.	Medium6	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable
Degrees, radians, gradiansGiven an angle written with six decimals in degrees, radians, or gradians, recover the integer degree value and the unit, or report that it is ambiguous.	Medium6	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable
Chess KnightInteractive task: find a knight's hidden starting square on an 8x8 board using at most 10 move attempts, where each reply says only whether the move stayed on the board.	Medium6	ImplementationBinary search+1	No attempts yet	1s	512 MB	Judgeable
Centennial WoodpeckerA ship moves right and can only turn right; stars block it. Count the energy spent before a coordinate exceeds 1e10, or report that it never happens.	Medium6	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Fallen ServerRestore a permutation from interval minimum and maximum notes, choosing the lexicographically smallest valid one, or report -1 if the notes contradict.	Medium6	GreedyMatrix+1	No attempts yet	1s	512 MB	Judgeable
Day StreakGiven solve times and a day length m, choose a shift t from 0 to m-1 to maximize the longest run of consecutive days with at least one solve.	Medium6	Two pointersSorting+1	No attempts yet	4s	512 MB	Judgeable
Gifting a SequenceBuild a permutation of 1 to N where the given binary search finds exactly K of its values, or report NO if no such permutation exists.	Medium6	ArrayBinary search+1	No attempts yet	1s	512 MB	Judgeable
Billboard AnnouncementsEach billboard exists from day S_i until the next multiple of T; find the fewest visit days so every billboard is seen at least once.	Medium6	IntervalsGreedy+2	No attempts yet	2s	1024 MB	Judgeable
Build The GridColor an N x N grid so the white cells form one connected region, every black cell touches a white cell, and the row and column black counts are both permutations of 0 to N-1.	Medium6	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
Coins and BoxesStarting at 0 on a line, find the minimum walking distance needed to open all N boxes, where each box consumes one coin picked up from the coin positions.	Medium6	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
Edges, Colors and MSTGiven a connected graph whose red edges form a spanning tree, find the lexicographically smallest weight permutation so that every MST edge is red.	Medium6	Topological sortTree+2	No attempts yet	2s	1024 MB	Judgeable
Hidden RookFind the cell of a hidden rook on an n by m board using at most 4 queries that count the cells a rectangle has under attack.	Medium6	Binary searchMath	No attempts yet	15s	256 MB	Judgeable
Stone Piles Game 2Three piles of stones: each move takes one stone from each of two nonempty piles, and the player who cannot move wins. Print the winner for T test cases.	Medium6	Game theoryMath	No attempts yet	1s	1024 MB	Judgeable
Expression Completion GameGiven target N from 1 to 100, decide the winner of the game where players append numbers 1 to 5 or shout a valid expression that reaches N.	Medium6	Game theoryBrute force+1	No attempts yet	1s	1024 MB	Judgeable
Attack OrderGiven minions with attacks a_i and buff values b_i, decide whether some left-to-right order keeps attacks non-increasing for every possible choice of buff targets.	Medium6	GreedySorting+1	No attempts yet	2s	512 MB	Judgeable
Diameter TwoGiven n and k, build the fewest-edge graph with diameter at most 2 where k nodes have degree 1 and the rest have degree at least 2, or report -1.	Medium6	GraphMath+1	No attempts yet	2s	512 MB	Judgeable
Implemented IncorrectlyCount the permutations of length n on which the rotate-when-smaller procedure fails to return the cyclic shift that starts with 1.	Medium6	CombinatoricsSimulation+1	No attempts yet	2s	512 MB	Judgeable
Even ForestGiven a tree with up to 10^6 vertices, find the fewest edges to remove so every resulting component is a tree whose leaves are all at even distance from each other.	Medium6	TreeDFS+2	No attempts yet	3s	512 MB	Judgeable
SurveySplit a budget of m dollars into n nonnegative shares, assigned to members at random, to maximize the expected number of members whose threshold is met.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	512 MB	Judgeable
Tri-Color PuzzleCount the ways to color a triangular grid of hexagon cells, with some cells fixed, so every upward triple is all one color or all three colors.	Medium6	MathMatrix	No attempts yet	1s	1024 MB	Judgeable
Checker SlideFind the minimum number of sliding moves that takes four checkers on a 6x6 board from a start layout to a target layout, and output the moves.	Medium6	BFSSimulation+2	No attempts yet	1s	1024 MB	Judgeable
How Many Unicycles in a Broken WheelCount the spanning unicycles in a broken wheel graph of size m, printing the count modulo 100007.	Medium6	Dynamic programmingGraph+1	No attempts yet	1s	1024 MB	Judgeable
NeighborsFill an N by N grid with values 1 to N so each row and column is a permutation, with values across marked edges differing by 1 and all others by more than 1.	Medium6	BacktrackingMatrix	No attempts yet	1s	1024 MB	Judgeable
AntialiasingGiven a convex polygon and a pixel, find the fraction of the pixel's area inside the polygon as a reduced fraction.	Medium6	GeometryImplementation+1	No attempts yet	4s	1024 MB	Judgeable
Team ChangeAssign each student to team A, team B, or sit out, honoring requested teams and keeping rivals on different teams, while minimizing the number of sit-outs.	Medium6	GraphBFS	No attempts yet	3s	1024 MB	Judgeable
Cracker Barrel GameGiven a 15-peg triangular board with colored pegs and a target color, decide whether jump moves can leave exactly one peg of that target color.	Medium6	BacktrackingBrute force+1	No attempts yet	3s	1024 MB	Judgeable
Substitution Mania!Recover the order of up to 12 shuffled substitution ciphers from one known plaintext and ciphertext pair, then decrypt a new message.	Medium6	Brute forceHash map+1	No attempts yet	5s	1024 MB	Judgeable
Shortest and Longest LISConstruct two permutations of 1 through n that match the given '<' and '>' signs, one with the smallest possible LIS and one with the largest.	Medium6	GreedyArray+1	No attempts yet	3s	256 MB	Judgeable
1-Trees and QueriesGiven a tree and one extra edge x-y per query, decide whether a path from a to b with exactly k edges exists.	Medium6	TreeDFS+1	No attempts yet	4s	512 MB	Judgeable
Animal Observation (easy version)Place alternating red and blue k-wide camera windows over n days to maximize animals seen, where a cell watched by both cameras on the same day counts once.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	3s	512 MB	Judgeable
Palindrome Free StringsGiven a string of 0, 1, and ?, decide whether the ? characters can be filled so that no palindromic substring of length 5 or more appears.	Medium6	Dynamic programmingString+1	No attempts yet	Not set	1024 MB	Judgeable
Interesting IntegersCount the integers between A and B (inclusive) whose digit product is divisible by their digit sum.	Medium6	Dynamic programmingMath	No attempts yet	20s	1024 MB	Judgeable
Moving CellsEach column has one black segment that can be shifted up or down so that neighboring columns overlap. Find the minimum total number of shifts.	Medium6	Dynamic programmingSliding window	No attempts yet	1s	512 MB	Judgeable
Army of ClonesFind the most clones that can walk from room 1 to room n, where each room with at least as many droids as clones halves the army.	Medium6	Shortest pathGraph+1	No attempts yet	1.5s	512 MB	Judgeable
RaceGiven n runners on parallel tracks with start positions and speeds, find the largest group that can lie on one straight line at some moment.	Medium6	GeometryMath+1	No attempts yet	2s	512 MB	Judgeable
Railroad sortingCars on an input track must leave on an output track in ascending order, using two dead-end stacks and transfer moves. Print a command sequence of at most 2e6 commands.	Medium6	StackSimulation+1	No attempts yet	1s	512 MB	Judgeable
Table SplitGiven a table filled row by row with 1 to n*m, find the single vertical or horizontal cut that makes the two part sums as close as possible.	Medium6	MathBinary search+1	No attempts yet	1s	512 MB	Judgeable
Mutated DNAGiven an RLE-encoded DNA string, find one single insert, delete, or replace that gives the shortest encoded length and one that gives the longest.	Medium6	StringImplementation+1	No attempts yet	1s	512 MB	Judgeable
Jumping RobotFind the minimum starting agility for a circular route where agility rises by 1 per jump, and name a platform that succeeds with it.	Medium6	ArraySliding window	No attempts yet	1s	512 MB	Judgeable
New Year at the KindergartenCount the pairs (x, y) with x at most a and y at most b, not both zero, where x+y is divisible by n, for each test case.	Medium6	MathNumber theory	No attempts yet	1s	512 MB	Judgeable
GiftsPick a segment of length at least k, remove its k largest values, and maximize the sum of the remaining gifts.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	1s	512 MB	Judgeable
Maximum RestChoose workdays, each capped at W_i, so total work reaches M while the smallest gap between chosen workdays is as large as possible.	Medium6	Binary searchDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Traffic Volume SurveyGiven a connected graph with N cities and N roads and M vehicle groups, count for each road how many vehicles could use it on some simple path.	Medium6	GraphTree+1	No attempts yet	2s	1024 MB	Judgeable
Find the Hyper Spot to Lie Down InGiven an 11-dimensional N-cube with K obstacle cells, count the runs of at least two empty cells along each of the 11 axes.	Medium6	Hash mapSorting+1	No attempts yet	4s	1024 MB	Judgeable
Vote CountingFor each query, decide whether Jeonghu can strictly lead all rivals after adding x votes to himself and y votes to rivals, given online vote updates.	Medium6	GreedySorting+2	No attempts yet	1s	512 MB	Judgeable
Center StageGiven an array with point updates, find for each range query the maximum of A_b - A_a - A_c over indices a < b < c inside the range.	Medium6	Segment treeArray	No attempts yet	2s	512 MB	Judgeable
Cubic CycleGiven a 3-regular graph with up to 50 vertices, count its Hamiltonian cycles. The task calls for backtracking over edge choices with pruning.	Medium6	BacktrackingGraph+1	No attempts yet	2s	1024 MB	Judgeable
Similar SpacingPick K of N sites on a road so that the largest gap minus the smallest gap between adjacent chosen sites is as small as possible.	Medium6	Dynamic programmingBrute force	No attempts yet	2s	1024 MB	Judgeable
The Cross Covers EverythingCount ordered point pairs whose cross, formed by the x-range and y-range between the two points, covers every given point.	Medium6	SortingPrefix sum+1	No attempts yet	3s	1024 MB	Judgeable
Balanced numbersGiven N, sum every balanced number up to 10^N, where the first and last ceil(K/2) digits have equal digit sums, and print the total modulo 315.	Medium6	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
PhotoshootGiven a line of N cows marked G or H, find the fewest even-length prefix reversals needed to put as many Guernseys as possible at even positions.	Medium6	GreedyDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Because, Art!Given font and color grades, for each k find the minimum and maximum sum of products over k pairs that use distinct fonts and distinct colors.	Medium6	SortingGreedy	No attempts yet	0.3s	1024 MB	Judgeable
Expedition PlansGiven sailing, diving, and fixing costs along a cable, find the diagnosis order of repeaters that minimizes the worst-case total cost over all faulty segments.	Medium6	Dynamic programmingIntervals	No attempts yet	10s	1024 MB	Judgeable