Problems

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Total results29,414 problems

Subway
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Domino Prediction
Medium6
Prefix sum, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
I Can Feel My Grade in the Flying Test Papers
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Level Up
Medium6
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Absolute Game
Medium6
Game theory, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Alehouse
Medium6
Intervals, Sliding window+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Jane Eyre
Medium6
Simulation, Heap+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
One of Each
Medium6
Greedy, Stack+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tourism
Medium6
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sculptural Project
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hard Sculptural Project
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Building Boundaries
Medium6
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Keep it Cool
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fabricating Sculptures
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
0.3s
Memory limit
512 MB
Judgeable
Gluing Pictures
Medium6
Dynamic programming, String matching+2
No attempts yet
Time limit
0.3s
Memory limit
512 MB
Judgeable
Improve SPAM
Medium6
Graph, DFS+2
No attempts yet
Time limit
0.3s
Memory limit
512 MB
Judgeable
Polygon
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Assessing Genomes
Medium6
String, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bouldering
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Historical Maths
Medium6
Math, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Keeping the Dogs Out
Medium6
Math, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Firetrucks Are Red
Medium6
Union-find, Graph+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
ACM
Medium6
Sorting, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Slagalica
Medium6
Graph, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Smallest Regular Subpolygon
Medium6
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Is There a Divisor?
Medium6
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Binary Number Game
Medium6
BFS, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ggeureuda Gimgganom
Medium6
Binary search, Array+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Robot Assembly
Medium6
Union-find, Implementation+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Fraction
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Model Crystal
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chisam's Playlist
Medium6
Simulation, Hash map+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Give Me Back My Binary Tree!!!
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Water Slide at Catholic University??
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Automatic Control Machine
Medium6
Bit manipulation, Brute force+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Largest Quadrilateral
Medium6
Geometry, Two pointers+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Have You Ever Sorted an Array?
Medium6
Sorting, Implementation+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Functional Analysis
Medium6
Tree, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Two Coins Unlimited
Medium6
BFS, Graph+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Bob in Wonderland
Medium6
Tree, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ponk Warshall
Medium6
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Ramen Buying (Large)
Medium6
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Commemorative Race
Medium6
Dynamic programming, Topological sort+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Convoy
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Fast Forwarding
Medium6
BFS, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Penguin Fall Response Committee
Medium6
Greedy, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
2xN Pretty Tiling
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rubber Duck Lovers Club
Medium6
Greedy, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Railway Tour
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Milk Pumping
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Milk Visits
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
The Great Feast
Medium6
Graph, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Team Practice
Medium6
Dynamic programming, Combinatorics
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Swapping Places
Medium6
Topological sort, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Counting Trees
Medium6
Combinatorics, Tree+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Splitting DNA
Medium6
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Visibility
Medium6
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Time is Mooney
Medium6
Dynamic programming, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Berry Picking
Medium6
Greedy, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Gold Rush
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Password
Medium6
DFS, Backtracking+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Three Towers
Medium6
Sliding window, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
LJUST
Medium6
String, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
ASLRDR
Medium6
Greedy, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
DISH
Medium6
String, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Politicians
Medium6
Graph, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Avoiding Surveillance
Medium6
Brute force, Backtracking+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Weapon Engineering
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Just Long Neckties
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
JJOOII 2
Medium6
Greedy, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Post Office 2
Medium6
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Post Office 3
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hall's Theorem
Medium6
Graph, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Easy Win
Medium6
Bit manipulation, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Two Teams
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Mineral 2
Medium6
Simulation, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Mini Battleship
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
6s
Memory limit
512 MB
Judgeable
Just So You Know
Medium6
Math, Greedy
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Deliveries
Medium6
Tree, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Valentine's Day
Medium6
Probability, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Money Sharing
Medium6
Greedy, Heap+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Just Shuffle the Input
Medium6
String matching, String+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Quicksort
Medium6
Sorting, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cosmic Cleaner
Medium6
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cultivating Mars
Medium6
Geometry, Binary search
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Journey
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rains
Medium6
Geometry, Probability+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Man in the middle
Medium6
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Gotta Catch 'Em All
Medium6
Binary search, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Football Hooliganism
Medium6
Dynamic programming, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Game of Nim Everywhere
Medium6
Game theory, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
FIFA World Cup
Medium6
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hawawshi Decryption
Medium6
Number theory, Math+1
No attempts yet
Time limit
15s
Memory limit
512 MB
Judgeable
Ice-cream Knapsack
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Bookface
Medium6
Sorting, Heap+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
A Permutation Problem
Medium6
Implementation, Math
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
The Destruction of the Crystals
Medium6
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hill
Medium6
Geometry, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Special Game
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cat
Medium6
String, String matching+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
SubwayEach station belongs to company A or B; find the route from station 0 to M that minimizes transfers first, then travel time, and report both.	Medium6	GraphShortest path+1	No attempts yet	1s	256 MB	Judgeable
Domino PredictionGiven XORs of consecutive domino numbers, answer queries for the XOR of positions x and y, or for the value at y when x holds d.	Medium6	Prefix sumBit manipulation+2	No attempts yet	1s	256 MB	Judgeable
I Can Feel My Grade in the Flying Test PapersSplit an array into K contiguous groups; maximize the minimum group sum.	Medium6	Binary searchGreedy+2	No attempts yet	1s	256 MB	Judgeable
Level UpGiven quests that give experience and cost time on two levels, find the minimum total time to clear both levels, with overflow carrying over, or -1 if impossible.	Medium6	Dynamic programmingArray	No attempts yet	2s	256 MB	Judgeable
Absolute GameAlice and Bob alternately delete elements from their own arrays until one element remains in each; Alice maximizes and Bob minimizes the final absolute difference.	Medium6	Game theoryGreedy+2	No attempts yet	1s	256 MB	Judgeable
AlehouseGiven n closed time intervals on a weekly circle, pick one interval of length at most k that intersects as many given intervals as possible.	Medium6	IntervalsSliding window+2	No attempts yet	1s	512 MB	Judgeable
Jane EyreSimulate Anna reading books in ASCII title order, with new books arriving on a schedule, and report the minute she finishes Jane Eyre.	Medium6	SimulationHeap+2	No attempts yet	1s	512 MB	Judgeable
One of EachGiven a sequence containing every value 1 to k at least once, find the lexicographically smallest subsequence that includes each value exactly once.	Medium6	GreedyStack+2	No attempts yet	2s	512 MB	Judgeable
TourismGiven a connected graph with city weights and a start city, find the maximum total weight of cities a walk from the start can visit without immediately reusing the road just taken.	Medium6	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Sculptural ProjectGiven a string of work and market days, cancel the fewest days so materials never run out and end at zero.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
Hard Sculptural ProjectGiven a string of 'w' (work, consume 1) and 'o' (rest, gain 1), delete the fewest characters so every prefix has more gains than work and the total balances, then count the ways.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	512 MB	Judgeable
Building BoundariesGiven three axis-aligned rectangles that can rotate in place, find the minimum area of a bounding rectangle that holds them without overlap.	Medium6	GeometryBrute force+2	No attempts yet	1s	512 MB	Judgeable
Keep it CoolPlace n new sodas into s slots of capacity d, each slot already holding some cold sodas in front, to maximize the chance that the next m students all take a cold one.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Fabricating SculpturesCount the arrangements of S stacks holding B blocks in total, modulo 1e9+7, where no stack is walled in by taller stacks on both sides.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	0.3s	512 MB	Judgeable
Gluing PicturesGiven a city string C, find for each friend name the fewest substrings of C that concatenate to form it, or -1 if impossible.	Medium6	Dynamic programmingString matching+2	No attempts yet	0.3s	512 MB	Judgeable
Improve SPAMGiven nested mailing lists, count how many messages reach client emails before deduplication and how many distinct emails are reached, both modulo 1e9+7.	Medium6	GraphDFS+2	No attempts yet	0.3s	512 MB	Judgeable
PolygonGiven segment lengths, choose a subset to form a non-degenerate convex polygon (largest side must be smaller than the sum of the rest) and report the maximum total length, or 0 if impossible.	Medium6	GreedySorting+2	No attempts yet	1s	512 MB	Judgeable
Assessing GenomesCompute each DNA string's smallest repeating unit length, then pair the two sets of scores to minimize the sum of squared differences.	Medium6	StringSorting+2	No attempts yet	2s	512 MB	Judgeable
BoulderingOn a grid of holds with grip costs, find the minimum total Euclidean path length from the bottommost hold to the topmost hold, where consecutive holds must be within reach r and total cost stays at most s.	Medium6	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
Historical MathsGiven the digit sequences of two factors and a product in an unknown base, find any base in which the multiplication holds, or report impossible.	Medium6	MathBrute force+2	No attempts yet	2s	512 MB	Judgeable
Keeping the Dogs OutGiven counts of square stones with power-of-two sides, decide whether all stones can tile a gap-free rectangle, and output one valid length and height or report impossible.	Medium6	MathGreedy	No attempts yet	2s	512 MB	Judgeable
Firetrucks Are RedGiven sets of numbers describing each of n people, output n-1 edges (p, q, r) where r appears in both sets, so that all people end up connected, or report that this is impossible.	Medium6	Union-findGraph+2	No attempts yet	5s	512 MB	Judgeable
ACMGiven a frozen ACM scoreboard where other teams' last-hour submissions are unknown, find the worst final rank the hero team could get.	Medium6	SortingSimulation+2	No attempts yet	1s	512 MB	Judgeable
SlagalicaOrder the puzzle pieces into a row with matching edges, starting at a left border and ending at a right border, minimizing the ids lexicographically.	Medium6	GraphGreedy	No attempts yet	1s	512 MB	Judgeable
Smallest Regular SubpolygonGiven a regular N-gon, find the smallest number of its vertices that themselves form a regular polygon.	Medium6	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
Is There a Divisor?Given a digit string, find a base B and a divisor X (both at most 10^9) making the string's value composite in base B, or report that none exists.	Medium6	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Binary Number GameGiven two binary strings, find the minimum number of single-bit flips (never the leading bit), increments, and decrements to turn the start number into the target.	Medium6	BFSDynamic programming+2	No attempts yet	1s	1024 MB	Judgeable
Ggeureuda GimgganomGiven N rolls, cut K cm off each end (one end if shorter than 2K, discard if at most K), then find the largest piece length P so the trimmed rolls yield at least M pieces.	Medium6	Binary searchArray+2	No attempts yet	1.5s	1024 MB	Judgeable
Robot AssemblyMaintain a growing set of unions between robot parts and answer, for each query part, how many parts currently belong to its robot.	Medium6	Union-findImplementation+1	No attempts yet	4s	1024 MB	Judgeable
FractionFor each query, print n decimal digits of a/b starting at the i-th digit after the decimal point, using the terminating representation when two exist.	Medium6	MathNumber theory+2	No attempts yet	1s	1024 MB	Judgeable
Model CrystalGiven the number of sides A and a temperature drop B, count the minimal crystals in the growing regular polygon.	Medium6	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Chisam's PlaylistSimulate playback where each song gains its playlist position per second, remove songs that reach threshold S, and answer max and lookup queries.	Medium6	SimulationHash map+2	No attempts yet	1s	1024 MB	Judgeable
Give Me Back My Binary Tree!!!Count the number of distinct binary trees with exactly E edges, where mirror images count as different trees, modulo 1e9+7.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	2s	1024 MB	Judgeable
A Water Slide at Catholic University??Given a directed graph, find the minimum number of starting vertices whose reachable sets cover every vertex.	Medium6	GraphBFS+2	No attempts yet	1s	1024 MB	Judgeable
Automatic Control MachineGiven up to 15 binary strings of length n, pick the fewest strings whose bitwise OR covers every position, or report -1.	Medium6	Bit manipulationBrute force+2	No attempts yet	2s	1024 MB	Judgeable
Largest QuadrilateralGiven up to 4096 integer points, find the largest area of a quadrilateral whose four vertices are chosen from those points.	Medium6	GeometryTwo pointers+1	No attempts yet	6s	1024 MB	Judgeable
Have You Ever Sorted an Array?Determine a hidden permutation of 1..N using only pairwise comparison queries, minimizing the number of queries across T games.	Medium6	SortingImplementation+2	No attempts yet	4s	512 MB	Judgeable
Functional AnalysisParse a PS-Lang program with nested blocks, detect redefinition or unbound errors, and report which top-level functions are pure.	Medium6	TreeHash map+2	No attempts yet	2s	512 MB	Judgeable
Two Coins UnlimitedTwo coins sit on a grid with walls; each button press slides both coins the same direction, and you must find the fewest presses that drop exactly one coin off the board.	Medium6	BFSGraph+2	No attempts yet	0.5s	512 MB	Judgeable
Bob in WonderlandGiven a tree of N connected links, find the minimum number of link reconnections needed to turn it into a path (each vertex has degree at most two).	Medium6	TreeGreedy+1	No attempts yet	2s	512 MB	Judgeable
Ponk WarshallGiven two equal-length strings over {A,C,G,T} with matching letter counts, find the minimum number of arbitrary swaps that turn the first string into the second.	Medium6	GreedyImplementation+2	No attempts yet	1s	512 MB	Judgeable
Ramen Buying (Large)Buy A[i] ramen from each factory using single-factory, adjacent-pair, or triple deals, minimizing the total cost.	Medium6	GreedyImplementation+2	No attempts yet	1s	64 MB	Judgeable
Commemorative RaceGiven a DAG of one-way roads, find the minimum over all single blocked roads of the longest path length after racers re-route optimally from the blocked point.	Medium6	Dynamic programmingTopological sort+1	No attempts yet	2s	512 MB	Judgeable
ConvoyGiven n people with drive times and k cars that seat five each, find the minimum total time to move everyone from the house to the stadium.	Medium6	SortingGreedy+1	No attempts yet	1s	512 MB	Judgeable
Fast ForwardingFind the minimum time to reach position t on a tape when speed can be tripled or divided by three once per second, and playback must end at normal speed.	Medium6	BFSDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Penguin Fall Response CommitteeGiven a line of N blocks with break costs and one marked penguin position, find the minimum total cost to break blocks so the penguin's group falls off the line.	Medium6	GreedyArray+2	No attempts yet	2s	512 MB	Judgeable
2xN Pretty TilingTile a 2xN grid with at most A dominoes and at most B 2x2 squares, rotating tiles freely, to maximize the sum of tile prettiness values.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	512 MB	Judgeable
Rubber Duck Lovers ClubPick exactly P of N members and assign each a value in [xi, yi] so the P values sum to E, or report that this is impossible.	Medium6	GreedyBacktracking+2	No attempts yet	1s	512 MB	Judgeable
Railway TourGiven an undirected graph, find the minimum number of edge-disjoint trails needed to cover every edge exactly once.	Medium6	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Milk PumpingGiven a graph with per-edge cost and flow, find the 1-to-N path maximizing (bottleneck flow)/(total cost), and print 10^6 times that value truncated.	Medium6	GraphShortest path+2	No attempts yet	1s	512 MB	Judgeable
Milk VisitsGiven a tree with each node labeled G or H, answer queries asking whether the path between two nodes contains at least one node of a given label.	Medium6	TreeDFS+2	No attempts yet	1s	512 MB	Judgeable
The Great FeastAssign A or B to 2n students on a circle so paired friends get different dishes and no three neighbors in a row match, or report that it is impossible.	Medium6	GraphImplementation	No attempts yet	2s	512 MB	Judgeable
Team PracticeCount assignments of N ordered problems to solvers A, B, C where A's count is a multiple of K, B never solves two in a row, and C solves at least one.	Medium6	Dynamic programmingCombinatorics	No attempts yet	1s	512 MB	Judgeable
Swapping PlacesGiven a line of animals where adjacent friend species may swap places, print the alphabetically smallest checkout order that can result.	Medium6	Topological sortGreedy+1	No attempts yet	1s	512 MB	Judgeable
Counting TreesCount the binary trees whose inorder traversal matches a given elevation sequence and where each child's label is at least its parent's, modulo 1000000007.	Medium6	CombinatoricsTree+1	No attempts yet	2s	512 MB	Judgeable
Splitting DNAGiven the lengths of N fragments in order, find the minimum total energy to split the original chain, where each cut costs the current chain length.	Medium6	Dynamic programmingIntervals+2	No attempts yet	1s	512 MB	Judgeable
VisibilityGiven N grid points, count ordered pairs (X, Y) such that Y lies strictly inside the 60 degree wedge opening south from X.	Medium6	GeometrySorting+2	No attempts yet	2s	512 MB	Judgeable
Time is MooneyFind a closed walk starting and ending at city 1 in a directed graph that maximizes collected city rewards minus C times the square of the number of days.	Medium6	Dynamic programmingGraph+2	No attempts yet	2s	512 MB	Judgeable
Berry PickingGiven N trees with B_i berries and K baskets that each hold berries from one tree, maximize the berries Bessie keeps after giving Elsie the K/2 fullest baskets.	Medium6	GreedyBinary search+2	No attempts yet	2s	512 MB	Judgeable
Gold RushGiven c Oshloobs and the gold price for each of n days, find the maximum Oshloobs at the end of day n, buying and selling gold each day and cashing out at the end.	Medium6	Dynamic programmingGreedy	No attempts yet	2s	512 MB	Judgeable
PasswordCount the Android-style 3x3 patterns whose segment directions match a given string, allowing any segment lengths, with no self-intersection allowed.	Medium6	DFSBacktracking+2	No attempts yet	2s	512 MB	Judgeable
Three TowersGiven a string of n blocks colored B, S, or C, find the longest contiguous segment that splits into at most three single-color towers with distinct heights.	Medium6	Sliding windowTwo pointers+2	No attempts yet	2s	512 MB	Judgeable
LJUSTRead lines up to ENDOFINPUT, wrap each to a width C, and justify any line whose length is at least floor(C/2) by spreading spaces left to right.	Medium6	StringImplementation+2	No attempts yet	2s	512 MB	Judgeable
ASLRDRReorder a string with adjacent swaps so it becomes a palindrome, reporting the minimum number of swaps or Impossible.	Medium6	GreedyTwo pointers+2	No attempts yet	2s	512 MB	Judgeable
DISHFor each pair of strings, output a shortest string that contains both input strings as substrings.	Medium6	StringDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
PoliticiansStarting from politician 1, each politician blames someone determined by who blamed them last, and you must find the guest of the K-th show for K up to 1e18.	Medium6	GraphSimulation+2	No attempts yet	1s	512 MB	Judgeable
Avoiding SurveillancePlace exactly 3 obstacles on empty cells of an N x N grid so that no teacher can see any student along its row or column.	Medium6	Brute forceBacktracking+2	No attempts yet	2s	256 MB	Judgeable
Weapon EngineeringOn a grid of at most 5 by 5 cells, place L-shaped triominoes (with the corner counted twice) so the covered cells' score is maximized.	Medium6	BacktrackingBrute force+2	No attempts yet	2s	256 MB	Judgeable
Just Long NecktiesFor each of the N+1 neckties, remove it and match the remaining N ties to N employees so the largest excess max(a-b, 0) is minimized.	Medium6	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
JJOOII 2Given a string of J, O, I and a level K, delete characters from the ends or middle to obtain K J's then K O's then K I's, minimizing middle deletions.	Medium6	GreedyTwo pointers+2	No attempts yet	2s	512 MB	Judgeable
Post Office 2Pick P of V village positions on a circular road for post offices so the total distance from each village to its nearest office is minimal.	Medium6	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Post Office 3Pick P of V village positions on a circular road of length L for post offices, minimizing the total distance from each village to its nearest one.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
Hall's TheoremGiven n and k, build a bipartite graph with n vertices on each side that has exactly k left subsets violating Hall's condition.	Medium6	GraphCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Easy WinGiven n piles of stones, for each x from 1 to n, determine whether the first player wins when each move removes 1 to x stones from one pile.	Medium6	Bit manipulationPrefix sum+1	No attempts yet	2s	512 MB	Judgeable
Two TeamsChoose the order in which to reveal each team's hidden last-hour problems so that teams A and B swap rank as many times as possible.	Medium6	GreedySorting+1	No attempts yet	2s	512 MB	Judgeable
Mineral 2Throw sticks alternately from left and right; each destroys the first mineral hit, then any cluster left floating falls straight down until it lands.	Medium6	SimulationGraph+2	No attempts yet	1s	512 MB	Judgeable
Mini BattleshipCount the ways to place k distinct ships of given sizes on an n by n grid so that hits, misses, and empty squares all match the observed board.	Medium6	BacktrackingBrute force+2	No attempts yet	6s	512 MB	Judgeable
Just So You KnowGiven an array, find the minimum expected number of yes/no conjectures needed to identify a uniformly random contiguous subarray, as an irreducible fraction.	Medium6	MathGreedy	No attempts yet	5s	512 MB	Judgeable
DeliveriesGiven a tree of warehouses with road lengths, find the fewest stops on the path from S to F when the truck can drive at most T km per charge.	Medium6	TreeGreedy+1	No attempts yet	2s	512 MB	Judgeable
Valentine's DayChoose a subset of n presents, each independently causing happiness with probability Pi, to maximize the probability that exactly one present causes happiness.	Medium6	ProbabilityGreedy+2	No attempts yet	2s	512 MB	Judgeable
Money SharingGiven a sequence of resupplies and loan requests, decide which requests to approve so that the balance never goes negative while declining as few as possible.	Medium6	GreedyHeap+2	No attempts yet	1s	512 MB	Judgeable
Just Shuffle the InputGiven strings s and t and a cyclic permutation p, find the fewest shuffles of t by p that make it a substring of s, or -1 if impossible.	Medium6	String matchingString+1	No attempts yet	3s	512 MB	Judgeable
QuicksortSort an array using at most n steps, where each step swaps any disjoint set of adjacent pairs.	Medium6	SortingGreedy+2	No attempts yet	2s	512 MB	Judgeable
Cosmic CleanerFor each test case, compute the total volume of the parts of n non-overlapping asteroids that lie inside a larger cleaning sphere.	Medium6	GeometryMath+1	No attempts yet	2s	512 MB	Judgeable
Cultivating MarsFor each growing factor (a, b), find the maximum of ax + by over all integer points in a convex polygon given by its vertices.	Medium6	GeometryBinary search	No attempts yet	2s	512 MB	Judgeable
JourneyCount binary strings of length N with no run of equal symbols longer than K, modulo 1e9+7.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
RainsGiven a grid of regular N-gons with side S and a brain of radius R, find the probability a random brain center lands close enough to a thread to be cut.	Medium6	GeometryProbability+2	No attempts yet	2s	512 MB	Judgeable
Man in the middleFind the lexicographically smallest uppercase string of length L whose polynomial hash mod 10007 equals H, or report that none exists.	Medium6	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Gotta Catch 'Em AllGiven N Pokemon points with types, find the smallest axis-parallel square that contains Pokemon of at least K different types.	Medium6	Binary searchSliding window+1	No attempts yet	2s	512 MB	Judgeable
Football HooliganismPartition a 2 by N grid of team labels into non-overlapping rectangles so that every rectangle is monochromatic, minimizing the number of 1 by 1 rectangles.	Medium6	Dynamic programmingImplementation+2	No attempts yet	2s	512 MB	Judgeable
Game of Nim EverywhereCount N in [L, R] where the Nim position (N, 2N, 3N) is a first-player win, i.e. where N xor 2N xor 3N is nonzero.	Medium6	Game theoryBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
FIFA World CupGiven the results of the first N-2 rounds of a round-robin group, decide for each team whether it can still finish in the top two, counting ties.	Medium6	GreedyImplementation	No attempts yet	2s	512 MB	Judgeable
Hawawshi DecryptionFor each test case, find the probability that key X appears among the first N outputs of the generator when the seed is chosen uniformly from [A, B].	Medium6	Number theoryMath+1	No attempts yet	15s	512 MB	Judgeable
Ice-cream KnapsackChoose exactly K ice creams so the largest calorie count among them is minimized, breaking ties by the largest total happiness, and report both values.	Medium6	GreedySorting+2	No attempts yet	5s	512 MB	Judgeable
BookfaceGiven daily line counts, find the fewest single-line edits so that every pair of days differs by at least d, with counts staying non-negative.	Medium6	SortingHeap+1	No attempts yet	2s	512 MB	Judgeable
A Permutation ProblemGiven a permutation of 1 to n, print an order that swaps every pair of values exactly once and sorts it, or print no if that is impossible.	Medium6	ImplementationMath	No attempts yet	3s	512 MB	Judgeable
The Destruction of the CrystalsGiven a board with crystals and bombs, find the most crystals a chain of bomb explosions can destroy when each bomb blasts its row or column.	Medium6	GraphBFS+1	No attempts yet	2s	512 MB	Judgeable
HillGiven two fixed endpoints and n segments with fixed lengths, find the highest y-coordinate a polygonal chain through them can reach, or report IMPOSSIBLE.	Medium6	GeometryGreedy+1	No attempts yet	1s	512 MB	Judgeable
Special GameDmytryk and Petro play n rounds of a card game with values 1 to 2n, and the task is to find the most rounds Dmytryk can win under optimal play.	Medium6	GreedySorting+1	No attempts yet	1s	512 MB	Judgeable
CatCount how many distinct strings you can form by joining a non-empty suffix of a with a non-empty prefix of b.	Medium6	StringString matching+2	No attempts yet	2s	512 MB	Judgeable