Problems

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Total results29,440 problems

Morning Three and Evening Four
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sequences of 1 and -1
Medium6
Combinatorics, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Coin Flips
Medium6
Math, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Fiibonacci Tree
Medium6
Tree, Recursion+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tiling a Grid
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
XYZ String
Medium6
Recursion, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Resident Registration Number
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Train
Medium6
Math, Simulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Largest Zero Submatrix
Medium6
Stack, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tree Coloring
Medium6
Tree, BFS+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Colored Sticks
Medium6
Union-find, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cubeditor
Medium6
String, Dynamic programming+1
No attempts yet
Time limit
0.5s
Memory limit
128 MB
Judgeable
Circle on Tiles
Medium6
Geometry, Math+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Flattening Tables
Medium6
Recursion, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tile Codes
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Box Puzzle
Medium6
Backtracking, Matrix+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Histogram
Medium6
Stack, Array+1
No attempts yet
Time limit
0.7s
Memory limit
128 MB
Judgeable
Making Couples
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Pibonacci
Medium6
Dynamic programming, Recursion+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Maximum Submatrix Sum
Medium6
Dynamic programming, Matrix+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Count Selections with GCD 1
Medium6
Number theory, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Run, Run
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Choosing Chicken-Fight Teams
Medium6
Union-find, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Card Bundles
Medium6
Stack, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Garden Pruning
Medium6
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Permutation Restoration
Medium6
Segment tree, Binary search+2
No attempts yet
Time limit
0.55s
Memory limit
128 MB
Judgeable
Cup Ramen
Medium6
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Mirror Numbers
Medium6
Combinatorics, String+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Sick Knight
Medium6
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Queuing at the Doctors
Medium6
Simulation, Queue+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Ordered Pairs with a Given GCD
Medium6
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Strange Keyboard
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Making a Rectangle
Medium6
Bit manipulation, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Paper Folding
Medium6
Divide and conquer, Recursion+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Adjacent Mastermind
Medium6
String, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Painting Roofs
Medium6
Dynamic programming, Tree+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Turning Off the Lights
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Partitioning for Fun and Profit
Medium6
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Harvest
Medium6
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Refueling
Medium6
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Border-Crossing Salesman
Medium6
Geometry, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Counting Full Binary Trees
Medium6
Dynamic programming, Tree+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bubble Sort
Medium6
Sorting, Array+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Array Rotation
Medium6
Simulation, Greedy+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Permutation
Medium6
Segment tree, Binary search+1
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Greatest Common Divisor of Ones
Medium6
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Minimum Cost Weight Sorting
Medium6
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Word Game
Medium6
Dynamic programming, String matching+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Finding the Maximum Score Path
Medium6
Backtracking, DFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Easy Skyline
Medium6
Stack, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Roman Numeral Sentences
Medium6
Greedy, String matching+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Horrible Sequence
Medium6
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Ball Replacement
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Find a Fraction
Medium6
Binary search, Number theory+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
1 && 3 Graph
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Shortest Non-subsequence
Medium6
Greedy, String matching+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cow Pizza
Medium6
Bit manipulation, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Rock-Paper-Scissors
Medium6
Dynamic programming, Probability+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Caesar Cipher
Medium6
String matching, String+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Wrestlers
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Logical Expressions
Medium6
Recursion, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cube Net
Medium6
Simulation, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Dice Battle Game
Medium6
Dynamic programming, Probability+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Greedy Panda
Medium6
DFS, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Moving a Log
Medium6
BFS, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Rectangles
Medium6
Intervals, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Critical Path
Medium6
Dynamic programming, Topological sort+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Excellent Villages
Medium6
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Map Labels
Medium6
Binary search, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Snail 3
Medium6
Simulation, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Matrix Construction
Medium6
Greedy, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Moving Through an Array
Medium6
Binary search, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Digital Friends
Medium6
String, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Choosing a Subarray 2
Medium6
Stack, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Race
Medium6
Dynamic programming, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Longest Arithmetic Progression
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Box Packing
Medium6
Simulation, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Image Compression
Medium6
Tree, Recursion+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Submatrix Range Queries
Medium6
Sliding window, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Collecting Jewels
Medium6
Binary search, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Trailing Zeros in a Combination
Medium6
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Minecraft
Medium6
Matrix, Greedy+1
No attempts yet
Time limit
1.52s
Memory limit
1024 MB
Judgeable
Line Drawing
Medium6
Union-find, Geometry
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Arranging a Meeting
Medium6
Simulation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Crossed Ladders
Medium6
Binary search, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Largest L Shape
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Unsweet Cookie
Medium6
Greedy, Binary search+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence Score
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Golomb Sequence
Medium6
Math, Recursion+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Finding Snakes
Medium6
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cascading Windows
Medium6
Simulation, String+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Farthest Pair of Points
Medium6
Geometry, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Restoring Calculation Expressions
Medium6
Backtracking, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Grid Triangles
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Atomic Energy
Medium6
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Baby Goat Lineup
Medium6
Combinatorics, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Multiplication Game
Medium6
Game theory, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Ferry
Medium6
Simulation, Queue+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Card Game
Medium6
Probability, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Elevator
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Morning Three and Evening FourGiven N banana weights, choose non-overlapping length-K blocks to move as a C-second group, minimizing total time and then the number of groups used, with output of chosen block positions.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	2s	128 MB	Judgeable
Sequences of 1 and -1Given M sequences of 1 and -1 of even length N, construct for each one a partner sequence whose elementwise product sums to zero, using at most N distinct partner sequences overall.	Medium6	CombinatoricsPrefix sum+2	No attempts yet	2s	128 MB	Judgeable
Coin FlipsFind the minimum number of row and column flips on an odd N by M 0/1 grid so every row and column has an even count of 1s, or output -1.	Medium6	MathBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Fiibonacci TreeGiven preorder indices of two nodes in a recursively built Fibonacci binary tree, compute the shortest L/R/U path between them without ever materializing the tree.	Medium6	TreeRecursion+2	No attempts yet	2s	128 MB	Judgeable
Tiling a GridCount the ways to fully tile an N by M grid (N, M up to 14) with 2x1 dominoes, modulo 9901.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
XYZ StringGiven a self-similar X/Y/Z rewriting sequence, answer queries about the stage N string's length, its k-th character, or the count of a given character without building the full string.	Medium6	RecursionDivide and conquer+2	No attempts yet	2s	128 MB	Judgeable
Resident Registration NumberGiven a 19-digit ID pattern with some digits erased, count completions that form a valid birth date and satisfy the modular checksum rule for the last digit.	Medium6	CombinatoricsMath+2	No attempts yet	2s	128 MB	Judgeable
TrainSimulate a traveler who must switch trains at every station under an hourly repeating schedule and find which train reaches station N, where N can reach a billion.	Medium6	MathSimulation+2	No attempts yet	2s	128 MB	Judgeable
Largest Zero SubmatrixGiven a binary matrix, find the maximum area rectangle of consecutive rows and columns that contains only zeros.	Medium6	StackDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Tree ColoringGiven a tree, assign colors 1 to n to vertices so adjacent vertices differ, minimizing the total cost equal to the sum of color numbers used.	Medium6	TreeBFS+2	No attempts yet	2s	256 MB	Judgeable
Colored SticksGiven colored-end sticks, decide if they can all be joined into one line where touching ends share the same color, which reduces to checking an Eulerian path exists.	Medium6	Union-findGraph+2	No attempts yet	2s	128 MB	Judgeable
CubeditorGiven a lowercase string of length up to 5000, find the maximum length of a substring that occurs at least twice, allowing overlapping occurrences.	Medium6	StringDynamic programming+1	No attempts yet	0.5s	128 MB	Judgeable
Circle on TilesGiven an even N, count how many unit tiles of an N by N grid are crossed by the circle inscribed tangent to all four sides.	Medium6	GeometryMath+1	No attempts yet	5s	128 MB	Judgeable
Flattening TablesParse nested HTML-style table layouts and output an equivalent single flat table using rowspan and colspan to preserve row and column alignment.	Medium6	RecursionTree+2	No attempts yet	1s	128 MB	Judgeable
Tile CodesCount distinct tilings of a 2xN board using 1x2, 2x1, and 2x2 tiles, where mirror-image tilings under left-right flip count as one.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Box PuzzlePlace n^2 rotatable cube boxes into an n by n grid so touching side faces match and outward faces show 0, then output the arrangement and rotation counts.	Medium6	BacktrackingMatrix+2	No attempts yet	2s	128 MB	Judgeable
HistogramGiven bar heights of a histogram, find the maximum-area rectangle that fits inside it using a stack-based approach.	Medium6	StackArray+1	No attempts yet	0.7s	128 MB	Judgeable
Making CouplesGiven lists of men's and women's personality values, form min(n, m) man-woman couples that minimize the total absolute difference of matched values.	Medium6	Dynamic programmingSorting+2	No attempts yet	2s	128 MB	Judgeable
PibonacciCompute a Fibonacci-like sequence defined with the irrational constant pi as a recursive step and output it modulo 10^18.	Medium6	Dynamic programmingRecursion+1	No attempts yet	2s	128 MB	Judgeable
Maximum Submatrix SumGiven an N by M integer matrix, find the maximum possible sum over all contiguous rectangular submatrices.	Medium6	Dynamic programmingMatrix+2	No attempts yet	2s	128 MB	Judgeable
Count Selections with GCD 1Given up to 50 integers, count non-empty subsets whose greatest common divisor equals 1, modulo 10,000,003.	Medium6	Number theoryCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Run, RunFind the maximum distance covered in N minutes of running and forced resting under a fatigue cap M, using dynamic programming over run-rest blocks.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	2s	128 MB	Judgeable
Choosing Chicken-Fight TeamsGiven friend/enemy relations among students where friends of friends are friends and enemies of enemies are friends, find the maximum number of valid teams.	Medium6	Union-findGraph	No attempts yet	2s	256 MB	Judgeable
Card BundlesGiven a shuffled permutation of 1 to N, output N-1 adjacent merges that combine bundles into a single bundle where each intermediate bundle holds consecutive integers.	Medium6	StackGreedy+2	No attempts yet	2s	128 MB	Judgeable
Garden PruningFind the minimum number of edge cuts needed to prune a tree down to exactly m vertices while keeping it connected.	Medium6	Dynamic programmingTree+1	No attempts yet	2s	128 MB	Judgeable
Permutation RestorationGiven the inversion sequence of a permutation of 1..N, reconstruct the original permutation using an efficient data structure.	Medium6	Segment treeBinary search+2	No attempts yet	0.55s	128 MB	Judgeable
Cup RamenGiven N jobs each taking one time unit with a deadline and a reward, choose which jobs to schedule to maximize total reward earned by finishing before deadlines.	Medium6	GreedyHeap+1	No attempts yet	2s	256 MB	Judgeable
Mirror NumbersCount how many numbers between A and B (up to 10^18) read the same when reflected in a mirror, using only digits 0,1,2,5,8 with 2 and 5 swapped.	Medium6	CombinatoricsString+2	No attempts yet	1s	64 MB	Judgeable
Sick KnightGiven an N by M board, find the max cells a knight limited to four specific diagonal jumps can visit, using all four move types once it makes 4+ moves.	Medium6	MathGreedy+1	No attempts yet	2s	128 MB	Judgeable
Queuing at the DoctorsSimulate visitors moving through a sequence of doctor offices, forming queues by arrival order and number, to find when the last person leaves.	Medium6	SimulationQueue+2	No attempts yet	1s	128 MB	Judgeable
Counting Ordered Pairs with a Given GCDCount ordered pairs (x, y) with x <= a, y <= b and gcd(x, y) = d for up to 50,000 queries.	Medium6	Number theoryMath+1	No attempts yet	2s	128 MB	Judgeable
Strange KeyboardGiven a string on a cursor-based keyboard, find the minimum Left/Right/Enter presses needed to print every character in alphabetical order.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
Making a RectangleGiven up to 16 sticks, choose four disjoint groups forming two equal-length pairs of sides to maximize the rectangle's area, or return -1 if impossible.	Medium6	Bit manipulationDynamic programming+2	No attempts yet	2s	256 MB	Judgeable
Paper FoldingGiven a crease pattern of length 2^N-1, decide if it could arise from repeatedly folding the right half of a strip onto the left half.	Medium6	Divide and conquerRecursion+2	No attempts yet	2s	128 MB	Judgeable
Adjacent MastermindGiven pairs of target and guess letter strings, compute black, grey, and white Mastermind scores by matching exact, then adjacent, then distant letters in priority order.	Medium6	StringGreedy+2	No attempts yet	1s	128 MB	Judgeable
Painting RoofsGiven a tree of houses and M paint costs, assign a color to every house minimizing total cost so that adjacent houses have different colors.	Medium6	Dynamic programmingTree+2	No attempts yet	2s	128 MB	Judgeable
Turning Off the LightsGiven a row of L bulbs and a fixed T-slot switch device that can be pressed at any aligned position any number of times, find the minimum number of bulbs left on.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Partitioning for Fun and ProfitGiven m, n and k, output the k-th lexicographically smallest partition of m into n non-decreasing positive parts.	Medium6	CombinatoricsDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
HarvestFind the maximum weighted profit from repeatedly harvesting a plant from either end of a row, where each harvest's value is multiplied by its pick order.	Medium6	Dynamic programmingArray+1	No attempts yet	1s	128 MB	Judgeable
RefuelingFind the minimum number of gas station stops a truck must make, given starting fuel and station positions with fuel amounts, to reach a village on a line.	Medium6	GreedyHeap+1	No attempts yet	2s	128 MB	Judgeable
Border-Crossing SalesmanGiven a convex polyhedron whose faces are countries, build the face-adjacency graph from shared edges and answer BFS shortest-path queries between faces.	Medium6	GeometryGraph+2	No attempts yet	2s	128 MB	Judgeable
Counting Full Binary TreesCount full binary trees with exactly n nodes and height exactly k, modulo 9901, using a height-bounded DP and subtraction trick.	Medium6	Dynamic programmingTree+2	No attempts yet	2s	128 MB	Judgeable
Bubble SortGiven an array, find the value of loop counter i when an early-exit bubble sort finishes sorting it.	Medium6	SortingArray+2	No attempts yet	2s	128 MB	Judgeable
Array RotationGiven a target permutation of ±1..N reachable by repeated reverse-and-negate interval operations starting from the sorted array, output a sequence of such operations that produces it.	Medium6	SimulationGreedy+1	No attempts yet	10s	128 MB	Judgeable
PermutationReconstruct a permutation of 1..N from A[i], the count of larger elements appearing before i, typically using a Fenwick tree or BIT with binary search.	Medium6	Segment treeBinary search+1	No attempts yet	0.5s	512 MB	Judgeable
Greatest Common Divisor of OnesGiven the digit counts N and M of two repunits, print their GCD, which equals the repunit with gcd(N,M) ones, requiring big-number output construction.	Medium6	Number theoryMath+1	No attempts yet	2s	256 MB	Judgeable
Minimum Cost Weight SortingFind the minimum total cost of swaps (cost = sum of the two masses swapped) needed to sort an array of distinct weights, using the classic cycle-decomposition trick with global minimum swap.	Medium6	GreedyMath+1	No attempts yet	2s	128 MB	Judgeable
Word GameGiven a string and a dictionary of words, find the minimum number of characters to delete from the string so the rest is a concatenation of dictionary words in order.	Medium6	Dynamic programmingString matching+2	No attempts yet	2s	128 MB	Judgeable
Finding the Maximum Score PathFind the maximum-score simple path from the top-left to bottom-right cell of an N x N grid moving only in four directions without revisiting cells.	Medium6	BacktrackingDFS+2	No attempts yet	2s	128 MB	Judgeable
Easy SkylineGiven the sequence of skyline breakpoints, find the minimum number of axis-aligned rectangular buildings that could produce that exact skyline.	Medium6	StackGreedy+1	No attempts yet	2s	128 MB	Judgeable
Roman Numeral SentencesFind the largest number whose canonical Roman numeral form can be picked out as an in-order subsequence of letters from a given sentence.	Medium6	GreedyString matching+2	No attempts yet	2s	128 MB	Judgeable
Horrible SequenceGiven M, find the max and min lengths of sequences with sum M that maximize the product, and sequences with product M that minimize the sum.	Medium6	MathNumber theory+2	No attempts yet	2s	128 MB	Judgeable
Ball ReplacementSimulate a 4-slot cache using an eviction strategy (like Belady's algorithm) that minimizes total insertions and replacements while processing a sequence of digit cards.	Medium6	GreedySimulation+1	No attempts yet	2s	128 MB	Judgeable
Find a FractionGiven N and K, find the K-th smallest reduced fraction p/q with 1<=p<q<=N in sorted order.	Medium6	Binary searchNumber theory+1	No attempts yet	2s	128 MB	Judgeable
1 && 3 GraphAnswer many shortest-path queries on a special connected graph where fewer than 3 vertices have degree at least 3, exploiting its path/cycle-like structure for efficiency.	Medium6	GraphShortest path+1	No attempts yet	4s	1024 MB	Judgeable
Shortest Non-subsequenceGiven a sequence of values from 1 to k, find the minimum length of a sequence over that alphabet that cannot be found as a subsequence of it.	Medium6	GreedyString matching+1	No attempts yet	2s	128 MB	Judgeable
Cow PizzaCount subsets of up to 20 toppings that avoid containing every topping of any given forbidden constraint set, using inclusion-exclusion or bitmask enumeration.	Medium6	Bit manipulationCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Rock-Paper-ScissorsCompute, as a reduced fraction, the probability that Hangseung reaches K round wins before Dongju in at most N rounds of rock-paper-scissors with ties possible.	Medium6	Dynamic programmingProbability+1	No attempts yet	2s	128 MB	Judgeable
Caesar CipherGiven a custom alphabet order, plaintext word, and cipher text, find all shift values for which decrypting yields the word exactly once, using string matching over a large alphabet.	Medium6	String matchingString+1	No attempts yet	2s	256 MB	Judgeable
WrestlersGiven wrestlers' strengths and ring powers determining pairwise match outcomes, find an ordering to meet the king that minimizes total awarded coins based on wins and preceding defeated opponents.	Medium6	SortingGreedy+1	No attempts yet	2s	128 MB	Judgeable
Logical ExpressionsParse a custom logical expression grammar with user-defined unary and binary operator truth tables, then evaluate it to true, false, or unknown given partial variable assignments.	Medium6	RecursionString+2	No attempts yet	1s	128 MB	Judgeable
Cube NetGiven three 6x6 grids each marking six connected unit cells, decide for each whether the shape folds into a valid cube net.	Medium6	SimulationMath+1	No attempts yet	2s	128 MB	Judgeable
Dice Battle GameGiven a defender count, simulate probabilistic dice battles to find the minimum starting attacker count achieving at least 50% win probability.	Medium6	Dynamic programmingProbability+1	No attempts yet	2s	128 MB	Judgeable
Greedy PandaFind the longest strictly increasing path through adjacent cells in an n x n grid using memoized DFS.	Medium6	DFSDynamic programming+1	No attempts yet	2s	256 MB	Judgeable
Moving a LogFind the minimum number of moves and 90-degree rotations to slide a 3-cell log from a start position to a goal position on a grid with obstacles.	Medium6	BFSSimulation+1	No attempts yet	2s	128 MB	Judgeable
RectanglesFind a line through the origin that intersects the maximum number of given axis-aligned rectangles, using each rectangle's angular interval from the origin.	Medium6	IntervalsSorting+1	No attempts yet	2s	128 MB	Judgeable
Critical PathOn a DAG, find the longest path length from source to target, then count edges that lie on at least one such longest path.	Medium6	Dynamic programmingTopological sort+1	No attempts yet	2s	512 MB	Judgeable
Excellent VillagesGiven a tree with village populations, choose a maximum-weight independent dominating set (no two chosen villages adjacent, every unchosen village adjacent to a chosen one).	Medium6	Dynamic programmingTree+1	No attempts yet	2s	128 MB	Judgeable
Map LabelsGiven city points, find the maximum label height so that fixed-ratio (3:1) rectangles anchored at each point never overlap, using binary search on the height with an efficient feasibility check.	Medium6	Binary searchSorting+1	No attempts yet	2s	128 MB	Judgeable
Snail 3Given large M and N, determine the number of turns in a clockwise spiral filling path through an M by N grid and its ending cell, without simulation.	Medium6	SimulationMath+1	No attempts yet	2s	128 MB	Judgeable
Matrix ConstructionGiven target row sums and column sums, construct any 0/1 n x n matrix satisfying both, or report impossibility.	Medium6	GreedyMatrix+1	No attempts yet	2s	128 MB	Judgeable
Moving Through an ArrayGiven an n x n grid, find a path from top-left to bottom-right that minimizes the difference between the maximum and minimum cell value on the path.	Medium6	Binary searchBFS+1	No attempts yet	1s	256 MB	Judgeable
Digital FriendsGiven three pairs of huge integers, classify each pair as friends, almost friends, or nothing based on digit-set equality achievable by at most one adjacent digit transfer operation.	Medium6	StringBrute force+1	No attempts yet	2s	128 MB	Judgeable
Choosing a Subarray 2Find a contiguous subarray maximizing (sum of elements) times (minimum element), and output that maximum score with the interval bounds.	Medium6	StackPrefix sum+1	No attempts yet	2s	128 MB	Judgeable
RaceGiven n checkpoints with scores that must be visited in increasing index order from and back to the origin, find the maximum score achievable within a runner's distance budget, for multiple runners.	Medium6	Dynamic programmingGeometry+1	No attempts yet	1s	128 MB	Judgeable
Longest Arithmetic ProgressionGiven up to 2000 nonnegative integers, find the maximum size subset that can be reordered into an arithmetic progression.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	128 MB	Judgeable
Box PackingSimulate dropping same-width plates into a box using column-wise collision like Tetris, opening a new box when the drop would exceed the height limit, and report each box's final height.	Medium6	SimulationArray+1	No attempts yet	2s	128 MB	Judgeable
Image CompressionBuild the quadtree of an image padded to the next power-of-two square, then count total nodes and the minimum nodes after sharing identical non-leaf subtrees.	Medium6	TreeRecursion+2	No attempts yet	2s	128 MB	Judgeable
Submatrix Range QueriesGiven an N x N matrix and K fixed-size BxB submatrix queries, output the max minus min value for each queried window efficiently.	Medium6	Sliding windowMatrix+1	No attempts yet	2s	128 MB	Judgeable
Collecting JewelsFind the maximum jewels collectible from a graph and returned to island 1 without exceeding any bridge's jewel-carrying capacity on any crossing.	Medium6	Binary searchGraph+1	No attempts yet	2s	128 MB	Judgeable
Trailing Zeros in a CombinationCompute the count of trailing zeros in C(n, m) for n up to 2 billion using prime factor exponents of 2 and 5 via Legendre's formula.	Medium6	Number theoryMath+1	No attempts yet	2s	128 MB	Judgeable
MinecraftGiven three 2D projections of a 3D 0/1 grid, construct any consistent 3D grid or report impossibility.	Medium6	MatrixGreedy+1	No attempts yet	1.52s	1024 MB	Judgeable
Line DrawingGiven up to 10,000 line segments, count connected groups formed by segments that touch, overlap, or intersect, using geometric intersection tests combined with union-find.	Medium6	Union-findGeometry	No attempts yet	2s	128 MB	Judgeable
Arranging a MeetingGiven fixed preference lists for everyone else, decide if Tae-hyun can misreport his own list in a Gale-Shapley style deferred acceptance process to get a truly better partner than honesty gives him.	Medium6	SimulationGreedy+1	No attempts yet	2s	128 MB	Judgeable
Crossed LaddersGiven two crossed ladder lengths and the crossing height above ground, compute the width of the alley between the buildings using binary search or numeric root finding.	Medium6	Binary searchMath+1	No attempts yet	2s	128 MB	Judgeable
Largest L ShapeGiven a binary grid, find the maximum-area L-shape (union of two rectangles sharing a lower-left corner, wider base and taller top) made entirely of 1-cells.	Medium6	Dynamic programmingMatrix+1	No attempts yet	2s	128 MB	Judgeable
Unsweet CookieChoose up to K starting points for length-D intervals over a timeline to cover the maximum number of given points.	Medium6	GreedyBinary search+1	No attempts yet	2s	512 MB	Judgeable
Sequence ScoreGiven n integers, pair up some of them (each element used at most once) to maximize the sum of chosen singles plus products of chosen pairs.	Medium6	GreedySorting+1	No attempts yet	2s	128 MB	Judgeable
Golomb SequenceGiven n up to 2 billion, compute the n-th term of the self-describing Golomb sequence efficiently.	Medium6	MathRecursion+1	No attempts yet	2s	128 MB	Judgeable
Finding SnakesCount connected 1-shapes in a grid that form a simple path (snake) with no possible one-cell extension at either end.	Medium6	GraphDFS+1	No attempts yet	2s	128 MB	Judgeable
Cascading WindowsParse windows with titles from an ASCII screen, sort them by title, and redraw them cascaded diagonally from the top-left corner.	Medium6	SimulationString+2	No attempts yet	2s	128 MB	Judgeable
Farthest Pair of PointsGiven up to 100,000 planar points, find the maximum squared Euclidean distance between any two points, typically via convex hull and rotating calipers.	Medium6	GeometryDivide and conquer+1	No attempts yet	1s	128 MB	Judgeable
Restoring Calculation ExpressionsInsert +, -, or * between digits of a string (length up to 9, no leading zero numbers) to produce all expressions evaluating to 2000, sorted lexicographically.	Medium6	BacktrackingBrute force+1	No attempts yet	1s	128 MB	Judgeable
Counting Grid TrianglesCount triangles with positive area formed by choosing three distinct lattice points from an (N+1) by (M+1) grid.	Medium6	CombinatoricsMath+1	No attempts yet	2s	128 MB	Judgeable
Atomic EnergyGiven a forest built from energy-state vertices connected by edges whose weight equals a proton energy, pick an independent set of vertices maximizing the sum of values (weighted maximum independent set on a forest).	Medium6	Dynamic programmingTree+1	No attempts yet	2s	128 MB	Judgeable
Baby Goat LineupGiven binary labels A through B, find the X-th label when ordered first by popcount then by numeric value.	Medium6	CombinatoricsBit manipulation+1	No attempts yet	2s	128 MB	Judgeable
Multiplication GameDetermine, given a real number X and up to 6 multiplier cards at most 0.9, which player forces X below or equal to 1 first under optimal play.	Medium6	Game theoryMath+1	No attempts yet	2s	128 MB	Judgeable
FerrySimulate a shuttling ferry with capacity M and crossing time t, picking up waiting passengers with priority for those who arrived earlier, and output each passenger's arrival time on the opposite bank.	Medium6	SimulationQueue+1	No attempts yet	2s	128 MB	Judgeable
Card GameGiven 9 piles of 4 cards, compute the probability that repeatedly removing a uniformly random matching-rank pair of top cards clears all cards.	Medium6	ProbabilityDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
ElevatorChoose elevator stop floors in a 31-story building to minimize the last employee's arrival time, given elevator move/stop costs and stair costs.	Medium6	Dynamic programmingGreedy+1	No attempts yet	2s	128 MB	Judgeable