Problems

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Total results29,355 problems

Password
Medium6
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Wolverine and the Bookshelf
Medium6
Tree, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Learning is light, not learning is darkness
Medium6
Array, Number theory+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Diagram
Medium6
Dynamic programming, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Casino Trip
Medium6
Greedy, Linked list+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Nightmare
Medium6
Number theory, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
String Game
Medium6
String matching, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tree
Medium6
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Breaking the Cipher
Medium6
Dynamic programming, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cheezy dibbles
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Two Cakes
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lecture Downloads
Medium6
Simulation, Heap+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Traps
Medium6
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Control Purchase
Medium6
Segment tree, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Grand Parade
Medium6
Matrix, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Revolution
Medium6
String, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Smith
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
This Time, Problem C Is a String
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
K-Sort Game
Medium6
Game theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mathematics
Medium6
Implementation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Beetle Dinner
Medium6
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pumba's Water Reservoir
Medium6
Divide and conquer, Array+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Semi-Palindromes
Medium6
Dynamic programming, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lycanthropy
Medium6
Graph, Greedy+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Programming Contest
Medium6
Graph, Shortest path
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fuel stations
Medium6
Graph, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Billboard
Medium6
String matching, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Javalhalla
Medium6
Array, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Defense
Medium6
Binary search, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ransom
Medium6
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dancing Bits
Medium6
Bit manipulation, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Connectedness and Intersections
Medium6
Intervals, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Childhood Toy
Medium6
Greedy, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Experimental Treatment
Medium6
Graph, BFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Football Fields
Medium6
String matching, Geometry
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Berland Football Union
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Filming
Medium6
Dynamic programming, Geometry
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Great Six
Medium6
Graph, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hobbit, or There and Back Again
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Alchemy
Medium6
Math, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hold the Line!
Medium6
String matching, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Obi-Wan Kenobi's Sword Storage
Medium6
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Victory Parade
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
General Grievous
Medium6
Math, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Slippery Path
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cookies
Medium6
Geometry, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
War
Medium6
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Famine
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Death
Medium6
BFS, Graph+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Feed the Headcrab
Medium6
Math, Prefix sum
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Reagents
Medium6
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Harry Potter and the Battle for Hogwarts
Medium6
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Achtung!
Medium6
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cookies
Medium6
Dynamic programming, Game theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jump!
Medium6
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Salary
Medium6
Math, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Least Common Multiple
Medium6
Number theory, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Interview
Medium6
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Roads
Medium6
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Physical Education
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Complexity
Medium6
Matrix, Hash map
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fibonacci Strings
Medium6
Recursion, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Box
Medium6
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sum of Squares
Medium6
Math, Recursion+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
New Game
Medium6
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Save Our World!
Medium6
Binary search, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Professional Fence Decorator
Medium6
Segment tree, String matching
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Achromatic number of a graph
Medium6
Graph, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Binary Search
Medium6
Binary search, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
No Petya
Medium6
Recursion, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Design Project
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Project
Medium6
Tree, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Railway Transport
Medium6
Graph, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tables and Legs
Medium6
Greedy, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chimeras
Medium6
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Boundary Spell
Medium6
String matching, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Postal Reform
Medium6
Tree, Segment tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Big Sum
Medium6
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tikal
Medium6
Combinatorics, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ministry of Truth
Medium6
Prefix sum, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rounding
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cloud Over the City
Medium6
Prefix sum, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cockroach Extermination
Medium6
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Left!
Medium6
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Grant Spending
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
MP3 Player
Medium6
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Blackjack
Medium6
Probability, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Keyboard Solo
Medium6
Hash map, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
PIMM Party
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
String
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Square Root
Medium6
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Subtrees
Medium6
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Journey
Medium6
Tree, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ball Game
Medium6
Dynamic programming, Combinatorics
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Digital Display
Medium6
Greedy, Implementation+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Divisibility Game
Medium6
Game theory, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Zuma 2.0: The Return of the Idol Frog
Medium6
Dynamic programming, String
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Wooden Board
Medium6
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stop Overtime!!
Medium6
Greedy, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Unit Founding Event
Medium6
Greedy, Queue+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
PasswordRecover a hidden binary password of known length by asking whether chosen strings occur in it, using at most 1024 queries.	Medium6	StringString matching+1	No attempts yet	2s	1024 MB	Judgeable
Wolverine and the BookshelfFind the fewest book additions or removals that make each vertex equal the sum of its at most two children, with leaves holding at most one book.	Medium6	TreeDynamic programming	No attempts yet	2s	1024 MB	Judgeable
Learning is light, not learning is darknessGiven an array with point updates, answer range queries for the number of divisors of the segment's product, modulo 1000000007.	Medium6	ArrayNumber theory+2	No attempts yet	4s	1024 MB	Judgeable
DiagramGiven n column heights and a limit k on height changes, find the minimum total absolute change needed so that at most k adjacent pairs differ.	Medium6	Dynamic programmingSorting	No attempts yet	2s	1024 MB	Judgeable
Casino TripRemove cards from a row one at a time, scoring the mean of both neighbors or the one remaining neighbor; find the maximum total score.	Medium6	GreedyLinked list+1	No attempts yet	2s	1024 MB	Judgeable
NightmareGiven a, b, and d, find the fewest multiply or divide operations (factor at most d) that turn a into b, or -1 if impossible.	Medium6	Number theoryGreedy+1	No attempts yet	2s	1024 MB	Judgeable
String GameGiven a string, find the longest substring that has at least two non-overlapping occurrences in the string and print its length.	Medium6	String matchingBinary search+1	No attempts yet	2s	1024 MB	Judgeable
TreeGiven a binary search tree with keys but no values, assign each vertex a value from 1 to 10^9 so the rebuilt tree is a BST, or report -1 if impossible.	Medium6	TreeDFS+1	No attempts yet	2s	1024 MB	Judgeable
Breaking the CipherGiven a sequence of n numbers, find the sum over all subsegments of the count of distinct subsequences (empty included), modulo 1000000007.	Medium6	Dynamic programmingHash map+1	No attempts yet	2s	1024 MB	Judgeable
Cheezy dibblesEach second, Skipper eats one chip from every pack in a segment where all packs are non-empty. Find the most packs he can empty in k seconds.	Medium6	Dynamic programmingGreedy	No attempts yet	2s	1024 MB	Judgeable
Two CakesGiven two rectangles, find a non-vertical line y=px+q that splits each rectangle into two pieces of equal area.	Medium6	GeometryMath+1	No attempts yet	1s	1024 MB	Judgeable
Lecture DownloadsEach file starts at a given time and shares bandwidth v equally with the other active downloads. Output each file's finish time.	Medium6	SimulationHeap+1	No attempts yet	2s	1024 MB	Judgeable
TrapsPlankton picks at most k trap points ahead of him to maximize the chase time against SpongeBob, or the chase is infinite when v1 is at least v2.	Medium6	GreedyHeap+1	No attempts yet	2s	1024 MB	Judgeable
Control PurchaseCount the boxes Gru buys: each is paid C1 at shipping if his balance allows, otherwise C2 at delivery if the balance allows.	Medium6	Segment treeSorting+1	No attempts yet	2s	1024 MB	Judgeable
Grand ParadeGiven k and n, build an n by n matrix of primes up to 10^7 with exactly k distinct primes and equal divisor counts in every row and column, or print -1.	Medium6	MatrixNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
RevolutionCount the segments that are exactly k-good, meaning they start with a 0, end with a 1, contain a (k-1)-good segment, and are not (k+1)-good.	Medium6	StringPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
SmithPick a subset of the given integers whose product is greater than the product of the remaining integers, and print the chosen indices.	Medium6	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
This Time, Problem C Is a StringChoose K of N strings of length M so that their characters, rearranged, form the lexicographically smallest string.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
K-Sort GameStones are split at position K, and two players take turns swapping out-of-order pairs in each half. Find the winner under optimal play.	Medium6	Game theoryMath	No attempts yet	1s	1024 MB	Judgeable
MathematicsGiven a text with ^ symbols followed by numbers, for each ^ decide whether it can be an exponent and whether it can be a footnote in some split that maximizes the footnote count.	Medium6	ImplementationGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Beetle DinnerCount the integer-coordinate points on the full line through Timon and Pumbaa that lie inside or on a given circle.	Medium6	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Pumba's Water ReservoirPumba adds water to ranges of basins, each capped at m liters, and must answer range sum queries over k days.	Medium6	Divide and conquerArray+1	No attempts yet	4s	1024 MB	Judgeable
Semi-PalindromesFind the longest substring of S that is a semi-palindrome, where each half must be a semi-palindrome and equal characters must pair with equal characters.	Medium6	Dynamic programmingString	No attempts yet	2s	1024 MB	Judgeable
LycanthropyAt each neuron the wolf essence may block up to k outgoing synapses so that a signal never reaches neuron n, in an interactive game on a DAG.	Medium6	GraphGreedy+1	No attempts yet	5s	1024 MB	Judgeable
Programming ContestGiven which team members can solve each problem, find the maximum number of problems the team can solve and the minimum total penalty for that many.	Medium6	GraphShortest path	No attempts yet	2s	1024 MB	Judgeable
Fuel stationsGiven a DAG where each city except Samara has two outgoing roads, decide whether fuel stations can be placed so every route from Moscow to Samara has the same number of stations.	Medium6	GraphDynamic programming	No attempts yet	2s	1024 MB	Judgeable
BillboardGiven strings s and t, find the fewest consecutive pieces of t such that each piece appears as a substring of s.	Medium6	String matchingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
JavalhallaSimulate a small list language where sublists share storage with their parent, and print elements requested by get operations.	Medium6	ArrayImplementation+1	No attempts yet	2s	1024 MB	Judgeable
DefenseGiven a tree of k portals, pick n of them so the smallest pairwise distance is as large as possible, then print that distance.	Medium6	Binary searchTree+1	No attempts yet	2s	1024 MB	Judgeable
RansomFind the hidden population of each of n cities by asking at most n queries, each returning the product of a chosen subset.	Medium6	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Dancing BitsCount the ordered triples (x, y, z) with every value between L and R that satisfy (x \| y) == (y ^ z), where L and R are up to 5 * 10^8.	Medium6	Bit manipulationDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Connectedness and IntersectionsGiven segments on a line and query indices, find the largest set of pairwise crossing segments that includes each queried segment.	Medium6	IntervalsDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Childhood ToyGiven an array a and m segments, find the fewest segments to remove so that each position i is covered at most a_i times.	Medium6	GreedySegment tree+1	No attempts yet	2s	1024 MB	Judgeable
Experimental TreatmentGiven n pairs of pill types, pick one type from each pair so that type j is picked exactly c_j times, or report -1 if impossible.	Medium6	GraphBFS	No attempts yet	2s	1024 MB	Judgeable
Football FieldsGiven two convex polygons, decide whether one can be mapped onto the other using translations and the eight symmetries generated by axis and diagonal reflections.	Medium6	String matchingGeometry	No attempts yet	2s	1024 MB	Judgeable
Berland Football UnionGiven a weighted tree, find every vertex where the sum of squared distances to all other vertices is minimal.	Medium6	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
FilmingCount the ways to place camera operators on free seats of a triangular stadium so that no seat is filmed by two operators, modulo 1e9+7.	Medium6	Dynamic programmingGeometry	No attempts yet	1s	1024 MB	Judgeable
The Great SixCount six-warrior sets that contain a mutual-friend triangle plus three distinct helpers, each a friend of a different triangle member.	Medium6	GraphBrute force+1	No attempts yet	2s	1024 MB	Judgeable
Hobbit, or There and Back AgainFind a route from home that visits every place and returns home with the least total danger, then report its length and danger.	Medium6	Dynamic programmingSorting+1	No attempts yet	2s	1024 MB	Judgeable
AlchemyAfter each rod is painted, the task counts unit squares of an n by m grid with exactly t painted sides, for every t from 0 to 4.	Medium6	MathSorting+1	No attempts yet	2s	1024 MB	Judgeable
Hold the Line!For each position in a string of up to 500000 lowercase letters, find the longest odd-length substring centered there that equals a prefix of the string.	Medium6	String matchingString	No attempts yet	2s	1024 MB	Judgeable
Obi-Wan Kenobi's Sword StorageProcess a sequence of adds, pops from the right end, and a rotation that moves the left half of the swords to the right end, then print the final order.	Medium6	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Victory ParadeCount the arrangements of n distinct medal counts where the number of salutes is the same whether the left or right entrance is blocked, modulo 1e9+7, for n up to 500.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
General GrievousDecide whether n lightsabers, each lasting m seconds per blade or m/2 when both blades are lit, can measure exactly t seconds.	Medium6	MathSimulation	No attempts yet	2s	1024 MB	Judgeable
Slippery PathFind the shortest time for Luke to move from building A to building B on an icy grid, where sliding down ice has stopping rules that can break the package.	Medium6	GraphShortest path+2	No attempts yet	2s	1024 MB	Judgeable
CookiesSplit a given convex quadrilateral into exactly three trapezoids with nonzero area that do not overlap and together cover the whole quadrilateral.	Medium6	GeometryImplementation	No attempts yet	2s	1024 MB	Judgeable
WarGiven a row of country labels, find the fewest provocateur plantings that remove every enclave until the map is empty.	Medium6	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
FamineCount the ways to mark each cell of an n by m grid as starving or fed, respecting fixed cells, so every 2x2 square has two of each, modulo 1e9+7.	Medium6	CombinatoricsMath+1	No attempts yet	2s	1024 MB	Judgeable
DeathGiven a grid of lord numbers, find the largest connected set of cells that uses at most two distinct lord numbers and report its size and those numbers.	Medium6	BFSGraph+1	No attempts yet	5s	1024 MB	Judgeable
Feed the HeadcrabGiven a multiset of group sizes that changes over time, each query n asks for the sum of n mod k over all groups k in the multiset.	Medium6	MathPrefix sum	No attempts yet	3s	1024 MB	Judgeable
ReagentsGiven n reagent dangers, merge them into arithmetic means in any grouping until one remains, and find the maximum possible final danger.	Medium6	GreedyHeap+1	No attempts yet	2s	1024 MB	Judgeable
Harry Potter and the Battle for HogwartsApply k passes of bubble sort to a permutation of 1 to n and print the array after those passes.	Medium6	ArrayImplementation	No attempts yet	2s	1024 MB	Judgeable
Achtung!Order n distinct points into a closed route whose straight segments never cross or touch except at shared endpoints, or report that no such route exists.	Medium6	GeometrySorting+1	No attempts yet	2s	1024 MB	Judgeable
CookiesGiven 2n cookie weights, find the maximum total weight Nyusha can guarantee when the player with the lighter total picks first in each turn.	Medium6	Dynamic programmingGame theory+1	No attempts yet	2s	1024 MB	Judgeable
Jump!Pick a connected set of roads with at most k bricks in total, upgrading as many roads as possible to highways that cost c times their brick count.	Medium6	Minimum spanning treeUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
SalaryGiven k up to 10^18, find the k-th digit of the string formed by writing the cubes 1, 8, 27, 64, ... one after another.	Medium6	MathBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Least Common MultipleGiven n and k, count the multisets of k positive integers whose least common multiple is exactly n, modulo 10^9+7.	Medium6	Number theoryCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
InterviewGiven two sequences a and b, find the length of the longest subsequence of a that is strictly increasing and also a subsequence of b.	Medium6	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
RoadsGiven a connected graph with free and paid roads, keep a spanning tree with exactly k paid roads, or print -1 if none exists.	Medium6	Minimum spanning treeUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
Physical EducationConcatenate n rows of boys (B) and girls (G) in any order, then find the maximum number of boys standing at odd positions in the merged row.	Medium6	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
ComplexityCount the unordered pairs of k by k subgrids that are not similar, where similar means one becomes the other after flipping whole rows or columns.	Medium6	MatrixHash map	No attempts yet	2s	1024 MB	Judgeable
Fibonacci StringsGiven k (0 to 80), find the length of the longest palindrome that appears as a substring of the k-th Fibonacci string.	Medium6	RecursionString+1	No attempts yet	2s	1024 MB	Judgeable
Magic BoxDecide whether a ball of diameter D can sit in an L x D x D box so that no sword pierces it, where touching is allowed.	Medium6	GeometrySorting+1	No attempts yet	2s	1024 MB	Judgeable
Sum of SquaresSplit the numbers 0 to n-1 into two sets with equal sums and equal sums of squares, or report that no such split exists.	Medium6	MathRecursion+1	No attempts yet	2s	1024 MB	Judgeable
New GameTwo players move a chip on a matrix according to cell values; decide whether the first player wins, the second player wins, or the game is a draw.	Medium6	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
Save Our World!Given two groups of points, find the largest distance d at which k points can be chosen with no cross-group pair closer than d, and list them.	Medium6	Binary searchGraph	No attempts yet	2s	1024 MB	Judgeable
Professional Fence DecoratorGiven n colored slats, process range repaint queries and report whether two equal-length fence segments have the same colors.	Medium6	Segment treeString matching	No attempts yet	2s	1024 MB	Judgeable
Achromatic number of a graphGiven n, find the largest number of colors in a proper coloring of the n-cycle where every pair of colors meets on some edge, and output one such coloring.	Medium6	GraphMath+1	No attempts yet	2s	1024 MB	Judgeable
Binary SearchCount the pairs of an array of length n (values 1 to n) and a value x in 1 to n for which the given binary search returns true.	Medium6	Binary searchDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
No PetyaGiven n and k, find two numbers on Yatep's sheet whose difference is exactly k, or report that no such pair exists.	Medium6	RecursionDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable
Design ProjectCount the ways to tile an n by m floor with square tiles of any integer side, modulo 1e9+7, where n is up to 1000 and m is up to 6.	Medium6	Dynamic programmingBit manipulation	No attempts yet	2s	1024 MB	Judgeable
ProjectGiven each room's tiling time and the ordering constraints between rooms, find the minimum total time to finish k rooms.	Medium6	TreeDynamic programming	No attempts yet	2s	1024 MB	Judgeable
Railway TransportGiven a railway network with mines, processing plants, and cities, find the maximum profit from delivering goods to the cities.	Medium6	GraphImplementation	No attempts yet	2s	1024 MB	Judgeable
Tables and LegsGiven how many square tables have 0 to 4 legs, find the minimum minutes to unscrew and rescrew legs so that no table is left with 1, 2, or 3 legs.	Medium6	GreedyMath	No attempts yet	2s	1024 MB	Judgeable
ChimerasCount the integers n in [a, b] for which 1! + 2! + ... + n! is divisible by n.	Medium6	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
Boundary SpellGiven a string w, output a binary string where position i is 1 if the i-th cyclic shift of w has a nonempty proper prefix that is also a suffix.	Medium6	String matchingString	No attempts yet	2s	1024 MB	Judgeable
Postal ReformGiven a tree of city heights, process point updates to tower heights and answer the maximum height on the path between two cities.	Medium6	TreeSegment tree	No attempts yet	2s	1024 MB	Judgeable
Big SumGiven n up to 10^12, compute the sum over each divisor d of n of gcd(d, i) summed for i from 1 to n.	Medium6	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
TikalCount the distinct ways to place k identical figurines on the n sides of a regular n-gon, treating rotations as the same, modulo prime p.	Medium6	CombinatoricsNumber theory	No attempts yet	2s	1024 MB	Judgeable
Ministry of TruthSplit n issues into three contiguous, non-empty parts so that the gap between the largest and smallest part sums is as small as possible.	Medium6	Prefix sumBinary search+1	No attempts yet	2s	1024 MB	Judgeable
RoundingCount the real numbers with exactly m digits after the decimal point that the faulty digit-by-digit rounding turns into k.	Medium6	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
Cloud Over the CityGiven vertical and horizontal street strips and a cloud that shifts by a fixed vector each second, compute the total snow falling on the streets over T seconds.	Medium6	Prefix sumSorting+2	No attempts yet	2s	1024 MB	Judgeable
Cockroach ExterminationGiven a tree of n nests, find the fewest nests to poison so that every nest is within distance k of a poisoned nest.	Medium6	Dynamic programmingTree+1	No attempts yet	2s	1024 MB	Judgeable
Left!Find the fewest drill commands (left, right, about face, step forward) that move a three-cell soldier from its start figure to its end figure on a grid with obstacles, or print -1.	Medium6	BFSGraph+2	No attempts yet	2s	1024 MB	Judgeable
Grant SpendingAssign n grants, each released on a given day, to m projects with spending rates so all the money is spent by the earliest possible day.	Medium6	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
MP3 PlayerCount the permutations of 1 to n where no two consecutive numbers are adjacent, and output the count modulo m.	Medium6	CombinatoricsDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
BlackjackGiven two player cards and the casino's visible card in simplified blackjack, decide whether the player should hit or stand to maximize expected winnings from a one-dollar bet.	Medium6	ProbabilityDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Keyboard SoloGiven a typed word with at most one keyboard mistake, list the dictionary words that could have produced it, in lexicographic order, up to five.	Medium6	Hash mapString+1	No attempts yet	2s	1024 MB	Judgeable
PIMM PartyCount the ways to place X insiders in the empty cells of an N by M grid so that every insider and every outsider is happy.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
StringFind the fewest characters to append to s so it contains a subsequence split into blocks of equal letters with sizes a_1 through a_n.	Medium6	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
Square RootFor each case, decide whether A + sqrt(B) is less than, equal to, or greater than C + sqrt(D) for integers up to 10^9.	Medium6	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
SubtreesGiven a tree with n vertices, count the ways to choose k vertex-disjoint subtrees for each k from 1 to n, modulo 10^9.	Medium6	Dynamic programmingTree+1	No attempts yet	2s	1024 MB	Judgeable
JourneyGiven a tree of n cities, find the fewest new roads to add so that a route visits every city once and returns to the capital.	Medium6	TreeGreedy	No attempts yet	2s	1024 MB	Judgeable
Ball GameCount ways to place N identical balls into M identical boxes with at most K balls per box, modulo R.	Medium6	Dynamic programmingCombinatorics	No attempts yet	2s	1024 MB	Judgeable
Digital DisplayGiven a number shown on a seven-segment display, move at most K sticks between digits to form the smallest larger number, or report that none exists.	Medium6	GreedyImplementation+1	No attempts yet	5s	1024 MB	Judgeable
Divisibility GameTwo players take cards in turn, and the one whose sum is divisible by three wins. Find the winner under optimal play, or a draw.	Medium6	Game theoryDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Zuma 2.0: The Return of the Idol FrogGiven a circle of up to 20 letters, find the fewest balls left after repeatedly removing two equal letters or three vowels within any five consecutive balls.	Medium6	Dynamic programmingString	No attempts yet	5s	1024 MB	Judgeable
Wooden BoardSheets hang on a board, each held by a nail. Removing a sheet drops the nails piercing it, possibly cascading, and queries ask nail counts or remaining sheets.	Medium6	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
Stop Overtime!!Given N tasks with deadlines and required work sessions, find the fewest weekend overtime days needed to earn exactly M points while finishing every task on time.	Medium6	GreedyDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Unit Founding EventOrder N stages so each soldier joins its first preferred stage in that order and every stage meets its minimum headcount, or report -1.	Medium6	GreedyQueue+1	No attempts yet	1s	1024 MB	Judgeable