Problems

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Total results29,440 problems

Turistai
Medium7
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mercurialist
Medium7
Probability, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tea Time in the Grand Garden
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
LCP Queries
Medium7
Trie, String matching+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Edit distance on table
Medium7
Dynamic programming, Graph+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Game
Medium7
Brute force, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stone
Medium7
Dynamic programming, Math
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Nabi and Utility Poles (Easy)
Medium7
Dynamic programming, Geometry
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chunbae Out for a Walk
Medium7
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Two-Star Chunbae
Medium7
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
String
Medium7
String matching, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Merge the Books
Medium7
Greedy, Heap+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Intertwined
Medium7
Geometry, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Safari
Medium7
Dynamic programming, Sorting+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Server Overload
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Two-Handed Sort
Medium7
Greedy, Graph+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Why Hobanwoo was late for school 5
Medium7
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Blackboard Game
Medium7
Game theory, Sorting+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Elevated Profits
Medium7
Tree, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Journey of the Robber
Medium7
Tree, Union-find+1
No attempts yet
Time limit
4.5s
Memory limit
1024 MB
Judgeable
Latam++
Medium7
Stack, Prefix sum
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Hidden Art
Medium7
Math, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
So I Quit Coding
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Quietly, Completely, Forever
Medium7
Segment tree, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Make Them Flutter
Medium7
Game theory, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Couple Breaker Minwook (Small)
Medium7
Array, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Couple Destroyer Minuk (Large)
Medium7
Dynamic programming, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pearls
Medium7
Backtracking, DFS+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Bombardment
Medium7
Greedy, Sliding window+2
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Thwack!
Medium7
Game theory, String
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Building Roads
Medium7
Geometry, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
History in Numbers
Medium7
Segment tree, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Journey of Recovery
Medium7
Shortest path, Graph+2
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Digitalisation
Medium7
Greedy, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Apocalypse
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Based Zeros
Medium7
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
H-Shaped Figures
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jumping Frogs
Medium7
Sorting, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Same Scenery
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kimbap Heaven and Road Hell
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lexio
Medium7
Prefix sum, Greedy+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Driving Practice
Medium7
Greedy, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Palindrome Word Chain
Medium7
Game theory, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Square Number Circular Permutation
Medium7
Graph, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Serious Business
Medium7
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Star capture
Medium7
Geometry, Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Starry Night (Easy)
Medium7
Prefix sum, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Super Tree Smashing
Medium7
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Latin Squares
Medium7
Matrix, Two pointers+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
ENDLESS RAIN
Medium7
Greedy, Segment tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Traveling Salesman Robot
Medium7
Dynamic programming, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Petya and the Coins
Medium7
Graph, Union-find+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Beautiful Number
Medium7
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Roads are not a luxury but a way to travel
Medium7
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
OMOI
Medium7
Dynamic programming, Tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
GCD Connects
Medium7
Union-find, Math+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Workday Routine
Medium7
Binary search, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Binary Game
Medium7
Game theory, Trie+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Vanya and Jackets
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Open Olympiad in Design
Medium7
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Metropolis Development
Medium7
Binary search, Dynamic programming+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Shall We Play a Game?
Medium7
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fools and Roads
Medium7
Union-find, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Concentric Circles
Medium7
Math, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Maggie's Homework
Medium7
Segment tree, Math+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Expansion Work
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Gahui and the House
Medium7
Prefix sum, Sliding window+1
No attempts yet
Time limit
3.5s
Memory limit
1024 MB
Judgeable
Two Chessboards
Medium7
Graph, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Reconstructing a Tree
Medium7
Tree, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pizza for the Party
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
An Excellent Lecture
Medium7
Graph, Divide and conquer+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Black Box
Medium7
Simulation, Segment tree
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Lucky Draws
Medium7
Dynamic programming, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Product Delivery
Medium7
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Special Numbers
Medium7
Dynamic programming, Number theory+1
No attempts yet
Time limit
1.5s
Memory limit
2048 MB
Judgeable
Matrix Operations (Making a Beautiful Matrix)
Medium7
Matrix, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
What Should We Eat for Dinner?
Medium7
Graph, Divide and conquer+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Tree Game
Medium7
Game theory, Tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shojin's Spear
Medium7
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Arranging Adapters
Medium7
Greedy, Binary search+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Isolated Island
Medium7
Geometry, Shortest path+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Sparse Primes Under a Tight Memory Limit
Medium7
Math, Sorting+1
No attempts yet
Time limit
20s
Memory limit
32 MB
Judgeable
Projected Array
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Count many primes quickly with short code
Medium7
Number theory, Math+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Lucky Draws 2
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Party
Medium7
Sorting, Two pointers+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chayas
Medium7
Dynamic programming, Bit manipulation
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Fortune Telling
Medium7
Probability, Dynamic programming+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Flippy MEX
Medium7
Array, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Maximum After Erasing
Medium7
Array, Stack+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gold Stimulation Also Needs a Meal First
Medium7
Dynamic programming, String matching+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Padaengi's Cake Stacking
Medium7
Combinatorics, Probability+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Padaeng's Office Visit
Medium7
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Harmonic Functions
Medium7
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Paint the Map with Stains and Ink
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tangerine Tree
Medium7
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
C.S.G.
Medium7
Game theory, Number theory+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Bouncing Balls
Medium7
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fish Game
Medium7
Game theory, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Number of Permutations
Medium7
Array, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
TuristaiFind the shortest walk from city 1 to city N on an undirected road map whose number of roads is a multiple of K, and print its visit count.	Medium7	GraphBFS+2	No attempts yet	2s	1024 MB	Judgeable
MercurialistAlice drinks from X elixir, Y mercury, and Z yogurt bottles in random order; find her survival probability as a fraction modulo 998244353.	Medium7	ProbabilityCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Tea Time in the Grand GardenCount sequences of N non-negative integers, framed by zeros, whose total upward steps equal K, modulo 998244353.	Medium7	CombinatoricsMath+1	No attempts yet	2s	1024 MB	Judgeable
LCP QueriesGiven strings s_i and t_j, each query concatenates the listed t_j and asks for the sum of its LCP with every s_i.	Medium7	TrieString matching+1	No attempts yet	2.5s	1024 MB	Judgeable
Edit distance on tableGiven a grid of letters and a string T, find the smallest edit distance between T and any string spelled by a walk on the grid.	Medium7	Dynamic programmingGraph+1	No attempts yet	3s	1024 MB	Judgeable
GameAssign cars A, B, or C to each game so every car-use requirement holds, given at most d maps that suit all cars, or report -1.	Medium7	Brute forceGraph	No attempts yet	2s	1024 MB	Judgeable
StoneCount initial pile sizes within each range, after hiding k extra stones, that can be fully emptied by the two operations, modulo 10^9+7.	Medium7	Dynamic programmingMath	No attempts yet	1.5s	1024 MB	Judgeable
Nabi and Utility Poles (Easy)For each start pole p, pick a non-crossing pole chain monotone on both sides of p, maximizing wire length, and print its minimum squared cost.	Medium7	Dynamic programmingGeometry	No attempts yet	1s	1024 MB	Judgeable
Chunbae Out for a WalkGiven N tower heights, find the minimum total number of 1-unit raises so that every pair of adjacent towers differs in height by at least X.	Medium7	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
Two-Star ChunbaeGiven a tree of N mountains with current and target heights, find the minimum won spent on buying soil so soldiers from P can reach every target height.	Medium7	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
StringFor each query (i, r), count the lengths l from 1 to r where s[i:i+l-1] is lexicographically smaller than R(s[i+l:i+2l-1]).	Medium7	String matchingBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Merge the BooksMerge n book piles into one, where each merge costs the lighter pile's weight plus both wear values. Find the minimum total energy.	Medium7	GreedyHeap+1	No attempts yet	1.5s	1024 MB	Judgeable
IntertwinedGiven pillars and a rope of length d tied at the origin, find the pillar the rope ends up wrapping around as it sweeps counter-clockwise.	Medium7	GeometrySimulation	No attempts yet	1s	1024 MB	Judgeable
SafariGiven animals at grid points, each visible only in a time window, find the maximum total observation time for a car moving in L1 distance from (0, 0).	Medium7	Dynamic programmingSorting+1	No attempts yet	0.5s	1024 MB	Judgeable
Server OverloadGiven an n by n grid of access counts, choose at most k non-overlapping 1x3 horizontal windows to maximize the total covered sum.	Medium7	Dynamic programmingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Two-Handed SortGiven a permutation of 1 to N, find the fewest swaps between the first and last floor(N/2) positions that sort it ascending.	Medium7	GreedyGraph+2	No attempts yet	1s	1024 MB	Judgeable
Why Hobanwoo was late for school 5Given N cards with (a, b), find the order of use that maximizes the sum of meteor heights measured from the lowest point of the flight path.	Medium7	SortingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Blackboard GameGiven 3N integers, two players alternately mark and erase elements; decide whether the first player can make the red and blue sums differ.	Medium7	Game theorySorting+1	No attempts yet	0.5s	1024 MB	Judgeable
Elevated ProfitsGiven a tree of cities and a start city R, maximize the sum of visit index times popularity, where each newly visited city must neighbor an already visited one.	Medium7	TreeGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Journey of the RobberGiven a tree of N cities ranked by wealth, find for each city the nearest richer city, breaking distance ties by choosing the poorer one.	Medium7	TreeUnion-find+1	No attempts yet	4.5s	1024 MB	Judgeable
Latam++Count the substrings of a string made of lowercase letters, parentheses, and the operators + - * / that are valid arithmetic expressions.	Medium7	StackPrefix sum	No attempts yet	0.5s	1024 MB	Judgeable
Hidden ArtGiven a pattern of white, red, green, and blue pixels that repeats forever, decide whether some square has four differently colored corners.	Medium7	MathMatrix+1	No attempts yet	2s	1024 MB	Judgeable
So I Quit CodingGiven N opponents with skill and mental values, find the most matches Sejong can play while his mental value stays above 0, with rest days adding R.	Medium7	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Quietly, Completely, ForeverApply range chmin updates to an array in order, output the final array, and count elements that no later update changes after each step.	Medium7	Segment treeImplementation	No attempts yet	1s	1024 MB	Judgeable
Make Them FlutterTwo players take turns buying flower kinds from shops over N days, while each day one shop's flowers merge into another, and the task is to name who takes the last flower on the final day.	Medium7	Game theoryHash map+1	No attempts yet	1s	1024 MB	Judgeable
Couple Breaker Minwook (Small)Split a row of N people into the fewest contiguous groups, then reorder the groups so that no couple stands next to each other.	Medium7	ArrayGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Couple Destroyer Minuk (Large)Split a line of people into the fewest contiguous groups that can be reordered so no couple ends up adjacent, then list up to 100 valid arrangements.	Medium7	Dynamic programmingBacktracking+1	No attempts yet	1s	1024 MB	Judgeable
PearlsFind the lexicographically smallest closed, non-crossing grid path that fits the pearl string under Masyu rules and the shop's three limits.	Medium7	BacktrackingDFS+1	No attempts yet	5s	1024 MB	Judgeable
BombardmentSimulate the greedy strategy that repeatedly picks the integer center covering the most remaining points, taking the smallest center on ties, and print the centers in order.	Medium7	GreedySliding window+2	No attempts yet	7s	1024 MB	Judgeable
Thwack!Given a 1D board of black stones, white stones, and empty cells, list every first move that wins for the first player under optimal play.	Medium7	Game theoryString	No attempts yet	5s	1024 MB	Judgeable
Building RoadsConnect N city sites with roads so every pair is reachable, and find the smallest possible longest travel distance in the network.	Medium7	GeometryGraph+1	No attempts yet	2s	1024 MB	Judgeable
History in NumbersGiven n yearly estimates with range-add updates, decide for each query range whether the local minima of its run-compressed sequence are strictly increasing.	Medium7	Segment treeArray+1	No attempts yet	2s	1024 MB	Judgeable
Journey of RecoveryFind the worst-case delay if any flight on a fixed itinerary is cancelled and you rebook the fastest route, or report stranded.	Medium7	Shortest pathGraph+2	No attempts yet	8s	1024 MB	Judgeable
DigitalisationCount how many students end up admitted to their first and second priority schools after two rounds of capacity-limited matching.	Medium7	GreedySimulation	No attempts yet	2s	1024 MB	Judgeable
ApocalypseGiven a convex polygon whose infected region doubles in area each day by growing outward, find the last day each settlement survives.	Medium7	GeometryBinary search+1	No attempts yet	3s	1024 MB	Judgeable
Based ZerosFor each n, find the largest number of zero digits that n can have in any base from 2 to n, and list every base that reaches that count.	Medium7	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
H-Shaped FiguresCount ordered pairs of given segments (a, b) where P lies strictly inside a, Q lies strictly inside b, neither is collinear with PQ, and a and b are disjoint.	Medium7	GeometrySorting+1	No attempts yet	2s	1024 MB	Judgeable
Jumping FrogsGiven two sorted sets of n frog positions, find every possible number of frogs that jumped left, listed in increasing order.	Medium7	SortingPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
The Same SceneryCount the x-axis points whose view of the trees above has the same left-to-right order as Hoyoung's view from below the axis.	Medium7	GeometrySorting+1	No attempts yet	1s	1024 MB	Judgeable
Kimbap Heaven and Road HellGiven roads of 2, 3, or 6 minutes, determine whether a walk from district 1 can reach district N at exactly K minutes.	Medium7	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
LexioGiven each player's remaining card count in seating order, find the fewest point transfers needed to settle the turn when one transfer between any two players is allowed.	Medium7	Prefix sumGreedy+2	No attempts yet	1.5s	1024 MB	Judgeable
Driving PracticeFor each station where the wizard may appear, find the teleport station that lets the car run out of electricity farthest from the origin, and print it with the charge change.	Medium7	GreedyPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Palindrome Word ChainGiven lengths L to U, find who wins the palindrome word chain game between Hoyoung and Aran and how many words are used, modulo 1e9+7.	Medium7	Game theoryCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
Square Number Circular PermutationArrange the integers 1 to N in a circle so that every adjacent pair, including the first and last, sums to a perfect square, or report -1 if no arrangement exists.	Medium7	GraphNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Serious BusinessGiven a 3 by n grid and q paid offers that unlock ranges of the middle row, find the maximum score of a path from the top-left to the bottom-right cell.	Medium7	Dynamic programmingPrefix sum+1	No attempts yet	3s	1024 MB	Judgeable
Star captureGiven N integer star positions, find the minimum total length of the rope segments left after the capture steps, where the rope wraps stars in layers.	Medium7	GeometrySorting	No attempts yet	1s	512 MB	Judgeable
Starry Night (Easy)Given N stars whose brightness drops by 1 per Manhattan step, find the total brightness over all cells in a given rectangle.	Medium7	Prefix sumMath+1	No attempts yet	1s	512 MB	Judgeable
Super Tree SmashingGiven a weighted rooted tree and K, pick one node to maximize the number of its grandchildren within weighted distance K.	Medium7	TreeDFS+2	No attempts yet	2s	1024 MB	Judgeable
Latin SquaresCount the contiguous k by k square subgrids of the n by m template that have exactly k distinct pairs and no repeated pair in any row or column.	Medium7	MatrixTwo pointers+1	No attempts yet	10s	1024 MB	Judgeable
ENDLESS RAINFind the fewest paths to pre-install so that every path needed on day i is either pre-installed or built by morning i, one parasol per morning.	Medium7	GreedySegment tree+1	No attempts yet	1s	1024 MB	Judgeable
Traveling Salesman RobotFind the minimum time for a salesman and his robot to visit every city of a directed road network, where the robot can be carried and released at cities.	Medium7	Dynamic programmingShortest path+2	No attempts yet	2s	1024 MB	Judgeable
Petya and the CoinsGiven n coins and m pairs of coins that differ in material, find every coin that can be the unique copper one in a valid 3-coloring.	Medium7	GraphUnion-find+1	No attempts yet	6s	1024 MB	Judgeable
Beautiful NumberGiven two huge decimal numbers l and r (up to 10^5 digits), find x in [l, r] that maximizes the product of its digits.	Medium7	GreedyString+1	No attempts yet	2s	1024 MB	Judgeable
Roads are not a luxury but a way to travelAfter each one-way road is added to a DAG, find the fewest vertex-disjoint routes that together visit every city exactly once.	Medium7	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
OMOIPick pairs of non-ancestor inspectors so every manager is the closest common supervisor of some pair, minimizing the sum of their costs.	Medium7	Dynamic programmingTree	No attempts yet	2s	1024 MB	Judgeable
GCD ConnectsGiven n numbers, pick a spanning tree of pairs that maximizes the sum of gcd over its edges, and print that maximum sum.	Medium7	Union-findMath+1	No attempts yet	4s	1024 MB	Judgeable
Workday RoutineFind an integer first height and a common step so that the arithmetic progression has the smallest total absolute change from the given column heights.	Medium7	Binary searchSorting+1	No attempts yet	2s	1024 MB	Judgeable
Binary GameTwo players append bits to a binary string, and whoever creates a forbidden substring loses. Decide the winner or whether the game is a draw.	Medium7	Game theoryTrie+2	No attempts yet	2s	1024 MB	Judgeable
Vanya and JacketsAssign each of n days one jacket whose temperature range covers that day's temperature, never using the same jacket on two consecutive days.	Medium7	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
Open Olympiad in DesignGiven n required lengths, find the fewest letters needed to write n distinct strings of those lengths in strictly increasing lexicographic order.	Medium7	Binary searchGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Metropolis DevelopmentPick a set of intervals that covers every segment from 1 to k so that the largest total pressure on any segment is as small as possible.	Medium7	Binary searchDynamic programming+2	No attempts yet	5s	1024 MB	Judgeable
Shall We Play a Game?Burr must find Hamilton's secret positive integer n by querying x and receiving the reduced fraction of multiples of x among 1 to n, within a query limit.	Medium7	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Fools and RoadsFind every company for which some path between the two capitals uses none of its roads, and list their numbers in increasing order.	Medium7	Union-findDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable
Concentric CirclesTwo families of concentric circles have distinct centers; count the bounded regions that all the circles form together.	Medium7	MathGeometry+1	No attempts yet	2s	1024 MB	Judgeable
Maggie's HomeworkRange-assign updates overwrite digits, and each query asks for the sum of all substring values in a range that do not start with 0, modulo 1e9+7.	Medium7	Segment treeMath+1	No attempts yet	4s	1024 MB	Judgeable
Expansion WorkAfter each new sign is added, print the perimeter and area of the smallest convex polygon that contains all signs placed so far.	Medium7	GeometryBinary search+1	No attempts yet	3s	1024 MB	Judgeable
Gahui and the HouseFind the minimum total boundary cost of a rectangular hole with its bottom on y=1, where the width and height fall within given ranges.	Medium7	Prefix sumSliding window+1	No attempts yet	3.5s	1024 MB	Judgeable
Two ChessboardsGiven two N by N boards with N rooks each, find the minimum number of rook swaps between the boards so that no rook attacks another on either board, or print -1 if impossible.	Medium7	GraphGreedy	No attempts yet	1s	1024 MB	Judgeable
Reconstructing a TreeGiven two trees A and B on N vertices, find at most 2N edge-sliding operations that turn A into B, where each operation moves one edge endpoint to another vertex.	Medium7	TreeImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Pizza for the PartyGiven N pizzas, each with heating time a_i and hot time b_i on one microwave, find the most pizzas that can be hot at the same instant.	Medium7	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
An Excellent LectureFor each student with known true and false statements, find the first announced consequence after which the implications contradict what the student knows.	Medium7	GraphDivide and conquer+1	No attempts yet	3s	1024 MB	Judgeable
Black BoxGiven the output list Z of BlackBox, reconstruct an input list I of up to 200,000 integers such that BlackBox(I) equals Z.	Medium7	SimulationSegment tree	No attempts yet	1s	2048 MB	Judgeable
Lucky DrawsGiven n intervals, choose K points so that the number of intervals containing at least one chosen point is maximized.	Medium7	Dynamic programmingSegment tree+1	No attempts yet	2s	2048 MB	Judgeable
Product DeliveryGiven demand ranges for n stores along a rail line, find the fewest deliveries from city 0, each non-decreasing over a prefix, that bring every store's total within its range.	Medium7	GreedyArray+1	No attempts yet	1s	2048 MB	Judgeable
Special NumbersCount the numbers in [L, R] whose digit product is divisible by k, modulo 10^9+7, where k is up to 10^17 and R is up to 10^20.	Medium7	Dynamic programmingNumber theory+1	No attempts yet	1.5s	2048 MB	Judgeable
Matrix Operations (Making a Beautiful Matrix)From the N by N upper triangular matrix of ones, add p/q to whole rows or columns within 2N operations so every absolute row and column sum is at most N/4.	Medium7	MatrixMath+1	No attempts yet	2s	1024 MB	Judgeable
What Should We Eat for Dinner?Each friend adds a two-literal OR clause over menu features, and after each query the task is to report whether all clauses so far can be satisfied together.	Medium7	GraphDivide and conquer+1	No attempts yet	2.5s	1024 MB	Judgeable
Tree GameGiven a tree with a piece at S and a target E, decide whether Yoona should move first or second so that she wins the alternating walk game where visited vertices are blocked.	Medium7	Game theoryTree+1	No attempts yet	1s	1024 MB	Judgeable
Shojin's SpearGiven X, Y, and K, find the smallest M at least K that minimizes ceil(M/X) divided by ceil(M/(X+Y)).	Medium7	MathNumber theory	No attempts yet	1s	1024 MB	Judgeable
Arranging AdaptersGiven n chargers with widths and a power strip with s sockets, find the maximum number of chargers that can plug in at once without overlapping.	Medium7	GreedyBinary search+1	No attempts yet	4s	1024 MB	Judgeable
Isolated IslandGiven fence segments that split an island into regions, determine whether two neighboring regions need the same minimum number of fish to reach the ocean.	Medium7	GeometryShortest path+1	No attempts yet	8s	1024 MB	Judgeable
Sparse Primes Under a Tight Memory LimitGiven N, A, and B, print every prime p_i with index i congruent to B mod A, where primes up to N are indexed from zero.	Medium7	MathSorting+1	No attempts yet	20s	32 MB	Judgeable
Projected ArrayRotate N numbered points around the origin, project them onto the x-axis, and find the minimum number of inversions in the resulting label order.	Medium7	GeometrySorting+1	No attempts yet	3s	1024 MB	Judgeable
Count many primes quickly with short codeFor each test case, count the primes less than or equal to N, where N can be up to 10^12 when there is only one test case.	Medium7	Number theoryMath+1	No attempts yet	5s	1024 MB	Judgeable
Lucky Draws 2Given n intervals [A, B] within 1 to m, find for each K the maximum number of intervals that contain at least one of K chosen integer points.	Medium7	Dynamic programmingGreedy+1	No attempts yet	5s	1024 MB	Judgeable
PartyPair up girls with different personality types so each pair's happiness sum is at most k, maximizing the total happiness of all paired girls.	Medium7	SortingTwo pointers+1	No attempts yet	2s	1024 MB	Judgeable
ChayasCount the orders of n chayas along a road that satisfy m records, each saying one chaya lies between two others, modulo 998244353.	Medium7	Dynamic programmingBit manipulation	No attempts yet	8s	1024 MB	Judgeable
Fortune TellingGiven n tarot cards, output for each card the probability it survives repeated die-driven removal of every sixth card, as a value modulo 998244353.	Medium7	ProbabilityDynamic programming+1	No attempts yet	5s	1024 MB	Judgeable
Flippy MEXAfter each double-sided card is added, count how many distinct mex values are possible over all ways to flip the cards placed so far.	Medium7	ArrayGreedy+1	No attempts yet	2s	512 MB	Judgeable
The Maximum After ErasingGiven a permutation, sum the maximum of the remaining elements over every way to delete two disjoint intervals, modulo 10^9+7.	Medium7	ArrayStack+1	No attempts yet	1s	512 MB	Judgeable
Gold Stimulation Also Needs a Meal FirstCount the starting levels F_1 where the sums of exactly M ingredients inside the window [F_1, F_1 + D_K] match the plan exactly, shifted by F_1.	Medium7	Dynamic programmingString matching+2	No attempts yet	2s	512 MB	Judgeable
Padaengi's Cake StackingGiven N layer types with K copies each in random order, find the probability that every layer can be placed, modulo 1,000,000,007.	Medium7	CombinatoricsProbability+1	No attempts yet	1s	1024 MB	Judgeable
Padaeng's Office VisitFind the least time to walk from room 1 on floor 1 to room N on floor K, using corridors on identical floors and elevators that rise one floor at a time.	Medium7	GraphShortest path	No attempts yet	1s	1024 MB	Judgeable
Harmonic FunctionsGiven integer polynomials f and g of degree at most 4, decide whether f can reach g by repeatedly replacing f with a polynomial in harmony with it.	Medium7	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Paint the Map with Stains and InkGiven K, paint some cells of a 50x50 grid so that the monotone paths from (1,1) to (50,50) avoiding painted cells number exactly K.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
Tangerine TreeEach day, N pickers take fixed amounts from a tree with M tangerines in order, and the task is to find how many remain after 10^100 days.	Medium7	SimulationMath+1	No attempts yet	1s	1024 MB	Judgeable
C.S.G.Players alternately take cards coprime with every card already taken, and the player who cannot move loses. Determine the winner under optimal play.	Medium7	Game theoryNumber theory+2	No attempts yet	3s	1024 MB	Judgeable
Bouncing BallsGiven a small grid of balls, find the fewest moves (multi-jump sequences by one ball) that leave exactly one ball, or report impossible.	Medium7	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
Fish GameOtto and Dave alternate moves on a 2xN grid, each taking the fish in every cell they enter; find what each takes under optimal play.	Medium7	Game theoryPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Number of PermutationsCount pairs (i, j) where the first i elements of A and the first j elements of B together form a permutation of length i+j.	Medium7	ArrayPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable