Interview core

Mediums from real onsites

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Total results3,617 problems

Dotted Strips
Medium5
Greedy, Prefix sum
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
LED Scheme
Medium5
Graph, BFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Checkpoint running
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Game Board
Medium5
Prefix sum, Matrix+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Data Analysis
Medium5
Dynamic programming, Sorting+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Halma
Medium5
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Marss
Medium5
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Puju
Medium5
Two pointers, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Acute Triangles
Medium5
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mars Car Numbers
Medium5
Combinatorics, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Broken Address Bus
Medium5
Bit manipulation, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tree Isomorphism
Medium5
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Short Message 2
Medium5
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Great Treaty of Byteland
Medium5
Geometry, Sorting
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Maximizing Flight Efficiency
Medium5
Shortest path, Matrix+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Wrong Bubble Sort
Medium5
Sorting, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Study Schedule Planning
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Change Bulb States
Medium5
Greedy, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lost Purity
Medium5
Tree, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Robotai
Medium5
Binary search, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tower
Medium5
Stack, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Santa Claus
Medium5
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Vitamins
Medium5
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Making Rectangles
Medium5
Hash map, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Azber's Tooth Marks
Medium5
Array, Hash map+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Bridges
Medium5
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mountain Hike
Medium5
Sorting, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Trip Compulsion
Medium5
Sliding window, Union-find+2
No attempts yet
Time limit
24s
Memory limit
1024 MB
Judgeable
Animesh decides to settle down
Medium5
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Complete Tripartite
Medium5
Hash map, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Powered Addition
Medium5
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Robot Competition
Medium5
Binary search, BFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tournament
Medium5
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Discharge Mission
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
휴가 나가기
Medium5
Dynamic programming, Tree
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Brightline - Back to the Future
Medium5
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Know your ABC's
Medium5
Dynamic programming, Combinatorics
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Travels
Medium5
Dynamic programming, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Like a Bridge over Troubled Freeways
Medium5
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Water Contamination
Medium5
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Trasa
Medium5
Graph, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Train
Medium5
Prefix sum, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Asteroid belt
Medium5
Shortest path, Intervals
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gathering Search Results
Medium5
Sorting, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Exponentiation
Medium5
Math, Matrix+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Glass cutting
Medium5
Sorting, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cookies
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Potential Graph 1
Medium5
Matrix, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Drifting
Medium5
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Give Back My Streak!
Medium5
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Odd Even Odd Even
Medium5
Segment tree, Bit manipulation
No attempts yet
Time limit
0.5s
Memory limit
16 MB
Judgeable
Santa Chunbae's Gift Distribution
Medium5
Greedy, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chunbae's Special Heart
Medium5
Divide and conquer, Recursion+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stacking Plates
Medium5
Array, Stack+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Re-verse
Medium5
String matching, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Reavers
Medium5
Graph, Union-find+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Electronic Components
Medium5
Greedy, Sorting
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
MEXchange
Medium5
Greedy, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wasting time
Medium5
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hobanwoo's Reason for Being Late to School 3
Medium5
Stack, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Candy Rush
Medium5
Sliding window, Hash map+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Forward and Backward
Medium5
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Compressing Commands
Medium5
Trie, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Funicular Frenzy
Medium5
Array, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jungle Job
Medium5
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rigged Rock-Paper-Scissors (Small)
Medium5
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rigged Rock-Paper-Scissors (Large)
Medium5
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
A Pivotal Question
Medium5
Array, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Forest for the Trees
Medium5
Hash map, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Split Decisions
Medium5
Hash map, String+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Dinner for Introverts
Medium5
Math, Greedy
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Greatest Greatest Common Divisor
Medium5
Number theory, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Margo Leaves Megabyteburg
Medium5
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Snakes&Snakes
Medium5
BFS, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kitchen Timer
Medium5
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Weather Trends
Medium5
Sliding window, Queue+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Huh? Banned
Medium5
Dynamic programming, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rush & Slash
Medium5
Union-find, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Doll Exhibition
Medium5
Hash map, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Each to Their Own Square
Medium5
Hash map, Geometry
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Rush Hour
Medium5
Graph, BFS
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Strange sum
Medium5
Hash map, Sorting+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Cartel Nim Game
Medium5
Game theory, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Return of the Poop Game
Medium5
Greedy, Sorting
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Coloring the Flag
Medium5
Matrix, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Up and Down
Medium5
Array, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Olympiad
Medium5
Binary search, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Metro
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Nested Candy Boxes
Medium5
Greedy, Sorting+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Clean Socks
Medium5
Sorting, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
DDR
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gahee and the Tunnel
Medium5
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Lexicographically Largest Common Subsequence
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sum of Intersection Sizes
Medium5
Combinatorics, Hash map
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Subsequence MEX
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fruitful cooperation
Medium5
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Vasya and Cyclic Shifts
Medium5
String, String matching
No attempts yet
Time limit
0.6s
Memory limit
1024 MB
Judgeable
A Million Scarlet Roses
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Reckless Speleologists
Medium5
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
XOR Queries
Medium5
Trie, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Dotted StripsCut a strip of L squares into as many length-M pieces with exactly N dots each as possible, where only some squares have dots.	Medium5	GreedyPrefix sum	No attempts yet	3s	1024 MB	Judgeable
LED SchemeGiven LEDs as directed edges between controller outputs, decide for each LED whether it can be the only one lit, meaning no other path leads from its anode to its cathode.	Medium5	GraphBFS+1	No attempts yet	3s	1024 MB	Judgeable
Checkpoint runningGiven N checkpoint positions on a line and a trip limit K, find the minimum total distance to visit all checkpoints, returning to the origin after each trip of at most K checkpoints.	Medium5	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Game BoardFind the K by K subgrid (K odd) where the gap between the two players' summed Manhattan distances to the center is smallest.	Medium5	Prefix sumMatrix+1	No attempts yet	1s	1024 MB	Judgeable
Data AnalysisSplit N points, sorted by x, into K contiguous groups so the total absolute deviation of y from one horizontal line per group is minimized.	Medium5	Dynamic programmingSorting+1	No attempts yet	3s	1024 MB	Judgeable
HalmaGiven a grid of pieces, find every empty cell that the piece marked # can reach in one move, either by a single step or a chain of jumps, and mark those cells with +.	Medium5	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
MarssCount the square regions of size 2x2 or larger in an N by M grid whose two diagonals are all black and whose other cells are all white.	Medium5	Dynamic programmingMatrix	No attempts yet	1s	1024 MB	Judgeable
PujuGiven a row of N cells with thickets, find the largest plot Kazimir can reach after clearing thickets on a walk from S that uses at most K steps.	Medium5	Two pointersPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Acute TrianglesGiven N integer points (N up to 200), count the acute triangles they form, and how many of those are pairwise non-congruent.	Medium5	GeometrySorting+1	No attempts yet	2s	1024 MB	Judgeable
Mars Car NumbersGiven N, find the lexicographically largest permutation in the first half and the smallest in the second half of all permutations of 1 to N.	Medium5	CombinatoricsImplementation	No attempts yet	1s	1024 MB	Judgeable
Broken Address BusGiven memory values and a working-wire mask per query, return the sum of values at addresses whose set bits all lie in that mask.	Medium5	Bit manipulationDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Tree IsomorphismGiven two labeled trees with N nodes each, decide whether the first can be relabeled into the second, and if so print the new number for each node.	Medium5	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Short Message 2Given N planet names made of lowercase letters, find the shortest string that contains every name as a substring.	Medium5	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Great Treaty of BytelandGiven capital coordinates on a plane, list the kingdoms whose Voronoi cells are unbounded, which are the capitals on the convex hull boundary.	Medium5	GeometrySorting	No attempts yet	0.5s	1024 MB	Judgeable
Maximizing Flight EfficiencyCheck whether any direct flight is more expensive than a multi-stop route, and if not, count the direct flights that can be removed without changing any trip cost.	Medium5	Shortest pathMatrix+1	No attempts yet	0.5s	1024 MB	Judgeable
Wrong Bubble SortGiven N, output a length-N array of values from 0 to 10000 that Jeongyeon's bubble sort fails to sort correctly.	Medium5	SortingSimulation	No attempts yet	1s	1024 MB	Judgeable
Study Schedule PlanningAssign non-negative study hours to N subjects, with a total of at most T, to maximize the summed scores minus the fatigue penalty for the total hours.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Change Bulb StatesGiven N bulbs colored R, G, or B, find the fewest three-bulb operations (each shifts the colors one step) that make all bulbs one color, or -1.	Medium5	GreedyPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Lost PurityGiven a tree, add the fewest edges so that every vertex lies on a cycle, then print the endpoints of each added edge.	Medium5	TreeGreedy+1	No attempts yet	1s	1024 MB	Judgeable
RobotaiTwo robots start at both ends of a furrow of length L and plant M trees at given positions. Find the minimum time to plant all of them.	Medium5	Binary searchGreedy	No attempts yet	1s	1024 MB	Judgeable
TowerRepeatedly delete every monochrome run of at least K cubes from a tower until none remain, then print the surviving cubes from top to bottom.	Medium5	StackSimulation	No attempts yet	1s	1024 MB	Judgeable
Santa ClausGiven N houses and depots with gift counts, find how many gifts to load at the start and at each depot so the sleigh holds as few as possible at all times.	Medium5	GreedyArray+1	No attempts yet	1s	1024 MB	Judgeable
VitaminsGiven N tablets with their vitamin C, vitamin D, and price, find the minimum cost to get at least C mg of vitamin C and D mg of vitamin D.	Medium5	Dynamic programming	No attempts yet	2s	1024 MB	Judgeable
Making RectanglesPair up chosen sticks into rectangles that all share one perimeter, maximizing the total area of the rectangles.	Medium5	Hash mapSorting+1	No attempts yet	2s	1024 MB	Judgeable
Azber's Tooth MarksGiven sorted tooth mark positions, find every gap k where each mark has another mark exactly k away from it.	Medium5	ArrayHash map+1	No attempts yet	3s	1024 MB	Judgeable
BridgesFor each range L to R, find the bridge height M (floor average of the endpoints) and sum the scaffolding and tunnel costs over that range.	Medium5	SortingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Mountain HikePick peaks so each new one is at least as high as all visited and no farther from the top peak; maximize total charm.	Medium5	SortingDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Trip CompulsionGiven a weighted undirected graph, find the minimum possible gap between the longest and shortest road on a path from start to end.	Medium5	Sliding windowUnion-find+2	No attempts yet	24s	1024 MB	Judgeable
Animesh decides to settle downGiven n convex polygons, find the area of the region that lies inside all of them.	Medium5	GeometryImplementation	No attempts yet	1s	1024 MB	Judgeable
Complete TripartiteGiven an undirected graph, split the vertices into three nonempty sets, each independent, with every pair of sets fully joined by edges, or report -1.	Medium5	Hash mapGraph+1	No attempts yet	2s	1024 MB	Judgeable
Powered AdditionEach second x, you may add 2^(x-1) to any chosen elements. Find the smallest T that makes the array nondecreasing.	Medium5	GreedyArray+1	No attempts yet	1s	1024 MB	Judgeable
Robot CompetitionFind the largest side length of a square robot that can travel from the left edge to the right edge of a grid maze with wall cells.	Medium5	Binary searchBFS+2	No attempts yet	1s	1024 MB	Judgeable
TournamentGiven a bracket order A and k proposed orders, check whether each proposed order makes every pair of players meet in the same round as A.	Medium5	ArrayImplementation	No attempts yet	1s	1024 MB	Judgeable
Discharge MissionKim can reorder the floors of each base, so the task is to decide whether his combat power can beat every enemy across all N bases.	Medium5	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
휴가 나가기Given tasks with importance, processing time, and at most one prerequisite each, find the minimum total time to reach importance S.	Medium5	Dynamic programmingTree	No attempts yet	1s	1024 MB	Judgeable
Brightline - Back to the FutureGiven directed blue lines (aging riders) and red lines (rewinding riders), list every city reachable from city 1 where a rider arrives younger than they started.	Medium5	Shortest pathGraph	No attempts yet	2s	1024 MB	Judgeable
Know your ABC'sCount the strings with a A's, b B's, and c C's where no two adjacent letters match, modulo 10^9 + 7.	Medium5	Dynamic programmingCombinatorics	No attempts yet	2s	1024 MB	Judgeable
TravelsGiven cities joined by one-way rails from lower to higher numbers, with some tickets unsold, sum the pleasure of every trip of at least two cities, modulo 1e9+7.	Medium5	Dynamic programmingGraph	No attempts yet	1s	1024 MB	Judgeable
Like a Bridge over Troubled FreewaysPlace c crossings on the x-axis so the average of each animal's walk (\|y\| plus horizontal distance to the nearest crossing) is minimized.	Medium5	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
Water ContaminationGiven contaminated and important locations joined by connections, find the fewest connections to block so no important location gets contaminated.	Medium5	GraphBFS	No attempts yet	1s	1024 MB	Judgeable
TrasaGiven an undirected road graph, find the longest route that repeats no city and whose inner cities have exactly two roads each.	Medium5	GraphImplementation	No attempts yet	1s	1024 MB	Judgeable
TrainGiven passenger counts per car, find the minimum total number of car-to-car moves so that every car ends with exactly K passengers.	Medium5	Prefix sumGreedy	No attempts yet	1s	1024 MB	Judgeable
Asteroid beltFind the minimum vertical fuel needed to fly from the start square to the destination through empty row intervals, where horizontal flight is free.	Medium5	Shortest pathIntervals	No attempts yet	1s	1024 MB	Judgeable
Gathering Search ResultsGiven k search engine rankings of n results, output one combined ranking that minimizes the sum of squared position differences across all engines.	Medium5	SortingGreedy+1	No attempts yet	3s	1024 MB	Judgeable
ExponentiationGiven alpha, beta, and m, compute x^beta + 1/x^beta mod m, where x + 1/x = alpha and all inputs are below 2^64.	Medium5	MathMatrix+1	No attempts yet	3s	1024 MB	Judgeable
Glass cuttingGiven an M by N pane with K point defects, find the largest axis-parallel rectangle that has no defect strictly inside it.	Medium5	SortingBrute force+1	No attempts yet	1s	1024 MB	Judgeable
CookiesTwo brothers alternately take cookies to maximize their own score minus the other's, and the task asks for the final value of A-B.	Medium5	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Potential Graph 1Given a weighted connected graph, fix f at 1 for vertex 1 and 0 for vertex N, then find g_f(1) when g_f is zero at every interior vertex.	Medium5	MatrixGraph+1	No attempts yet	2s	1024 MB	Judgeable
DriftingFind the minimum weight path from vertex 1 to vertex N in a DAG where certain consecutive edge pairs (a, b, c) are forbidden.	Medium5	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
Give Back My Streak!Given daily problem counts, find the longest streak when a Streak Freeze covers zero-solve days and is rebought two days after each use.	Medium5	SimulationGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Odd Even Odd EvenGiven an array of N zeros, process Q queries that add w to a range and count the odd and even values in a range.	Medium5	Segment treeBit manipulation	No attempts yet	0.5s	16 MB	Judgeable
Santa Chunbae's Gift DistributionGiven N gifts priced from 0 to 3, pair them into N/2 pairs so that the sum of the XOR values of the pairs is as large as possible.	Medium5	GreedyImplementation	No attempts yet	1s	1024 MB	Judgeable
Chunbae's Special HeartGiven N and M, decide whether repeatedly splitting a heart into floor and ceiling halves and keeping one half can end at exactly M grams.	Medium5	Divide and conquerRecursion+1	No attempts yet	1s	1024 MB	Judgeable
Stacking PlatesGiven N plates of thickness 1 or 2, merge adjacent equal plates into one doubled plate to find the largest thickness that can be reached.	Medium5	ArrayStack+1	No attempts yet	1s	1024 MB	Judgeable
Re-verseGiven a song string of length N, find the maximum number of start seconds from 0 to N-1 where the song can be sung so that overlapping shouted letters agree.	Medium5	String matchingMath	No attempts yet	1s	512 MB	Judgeable
ReaversGiven each person's claim about another person's identity, find the fewest aliens that fit all the reports, with at least one human present.	Medium5	GraphUnion-find+1	No attempts yet	1s	512 MB	Judgeable
Electronic ComponentsGiven N component types with counts and placement times, find the minimum total time to place all components when two different types can be placed in one move.	Medium5	GreedySorting	No attempts yet	4s	1024 MB	Judgeable
MEXchangeGiven the prefix MEX sequence B, construct a permutation A that produces B, or report that no such permutation exists.	Medium5	GreedyImplementation	No attempts yet	1s	1024 MB	Judgeable
Wasting timeFind the longest time to first reach cell N from cell 1 when each cell's number sets the move length and at most two direction reversals are allowed.	Medium5	Dynamic programmingGraph+1	No attempts yet	1s	1024 MB	Judgeable
Hobanwoo's Reason for Being Late to School 3Logs are added in increasing length, and each spell cuts the longest log down to a threshold. Find the total length of the logs left after all N queries.	Medium5	StackSimulation	No attempts yet	1s	1024 MB	Judgeable
Candy RushFind the longest contiguous block of candies that contains exactly K brands, with each brand appearing the same number of times.	Medium5	Sliding windowHash map+1	No attempts yet	2.5s	1024 MB	Judgeable
Forward and BackwardGiven N up to 10^12, list every base from 2 to N in which N reads the same forward and backward, in increasing order.	Medium5	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Compressing CommandsGiven n absolute file paths, find the working directory that minimizes the total number of components in their relative forms.	Medium5	TrieTree+1	No attempts yet	2s	1024 MB	Judgeable
Funicular FrenzyGiven arrivals per minute and carriage capacity c, find the arrival minute that minimizes your funicular wait, earliest on ties, or report impossible.	Medium5	ArrayPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Jungle JobCount the connected subtrees of a rooted tree with n branches for each size k from 1 to n, modulo 1e9+7.	Medium5	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Rigged Rock-Paper-Scissors (Small)Count the non-empty subsequences of a rock-paper-scissors move string where no round won by lighter is immediately followed by a tie.	Medium5	Dynamic programmingString	No attempts yet	1s	1024 MB	Judgeable
Rigged Rock-Paper-Scissors (Large)Count the non-empty subsequences of smallant's moves where lighter, copying the previous move, never wins a round followed by a tie.	Medium5	Dynamic programmingString	No attempts yet	1s	1024 MB	Judgeable
A Pivotal QuestionGiven an array of unique integers, list every value that could be a quicksort pivot, meaning all elements before it are smaller and all elements after it are larger.	Medium5	ArrayPrefix sum	No attempts yet	2s	1024 MB	Judgeable
Forest for the TreesGiven a map of tree coordinates and sensor readings taken at an unknown heading, find the robot's grid position, or report Impossible or Ambiguous.	Medium5	Hash mapBrute force+1	No attempts yet	2s	1024 MB	Judgeable
Split DecisionsCount the word pairs that differ in exactly two adjacent letters, where no other pair in the list fits that same letter clue.	Medium5	Hash mapString+1	No attempts yet	6s	1024 MB	Judgeable
Dinner for IntrovertsFind the most introverts that can sit at a round table of N seats so each one has at least K free chairs across its two neighboring gaps.	Medium5	MathGreedy	No attempts yet	0.5s	1024 MB	Judgeable
Greatest Greatest Common DivisorGiven L and R with R - L at most 10^6, find two distinct integers in [L, R] whose greatest common divisor is as large as possible.	Medium5	Number theoryBrute force+1	No attempts yet	1s	1024 MB	Judgeable
Margo Leaves MegabyteburgGiven a grid with walls, decide whether Margo can walk from the dormitory to the airport using single steps and at most K two-cell jumps.	Medium5	BFSGraph+1	No attempts yet	2s	1024 MB	Judgeable
Snakes&SnakesFind the fewest turns for a piece to reach cell N, where each roll of 6 grants another roll in the same turn and teleports pull the piece back.	Medium5	BFSShortest path+1	No attempts yet	1s	1024 MB	Judgeable
Kitchen TimerSplit x into the fewest terms of the form 2^k - 1 (k at least 1) and output the number of terms minus one.	Medium5	GreedyMath+1	No attempts yet	2s	1024 MB	Judgeable
Weather TrendsGiven n daily temperatures and a window of m days, find the largest rise from an earlier day to a later day within that window.	Medium5	Sliding windowQueue+1	No attempts yet	20s	1024 MB	Judgeable
Huh? BannedChoose a subset of shout times so that no chosen shout falls in [t_i - b_i, t_i] of another chosen time, maximizing the sum of c_i.	Medium5	Dynamic programmingBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Rush & SlashWeeds are grouped by 8-neighbor connectivity, and the task asks for the minimum total Manhattan travel to cut all of them, returning to the origin after each cut except the last.	Medium5	Union-findHash map+1	No attempts yet	2s	1024 MB	Judgeable
Doll ExhibitionGiven an R x C table and N doll heights, find the maximum number of dolls visible from the front when each column shows strictly increasing heights.	Medium5	Hash mapGreedy	No attempts yet	1s	1024 MB	Judgeable
Each to Their Own SquareFor each test case, count the squares whose four corners are all among the given n points, stopping when n is 0.	Medium5	Hash mapGeometry	No attempts yet	3s	1024 MB	Judgeable
Rush HourDecide whether roads from intersection 1 can carry p cars per second to all dead-end neighborhoods, given each road's capacity.	Medium5	GraphBFS	No attempts yet	0.5s	1024 MB	Judgeable
Strange sumGiven a grid of colored cells, compute the sum of Manhattan distances over all pairs of cells that share a color.	Medium5	Hash mapSorting+1	No attempts yet	3s	1024 MB	Judgeable
Cartel Nim GameThree players take turns removing 1 to K stones (A and B may take at most K/2 each), and the player taking the last stone wins; find which team wins.	Medium5	Game theoryDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Return of the Poop GameGiven a start power D and monster and equipment rooms, find the most rooms Gunho can clear before losing to a monster.	Medium5	GreedySorting	No attempts yet	0.5s	1024 MB	Judgeable
Coloring the FlagGiven two N by M letter grids A and B, decide whether A can be turned into B by repeatedly recoloring a same-color connected region to any other color.	Medium5	MatrixBFS+1	No attempts yet	1s	1024 MB	Judgeable
Up and DownOrder all cards in one sequence so each adjacent pair differs by exactly 1, or report -1 if no such order exists.	Medium5	ArrayMath+1	No attempts yet	1s	1024 MB	Judgeable
OlympiadGiven long-round scores, a cutoff place p, and the maximum short-round score, label each participant as always advancing, never advancing, or depending on the short round.	Medium5	Binary searchSorting	No attempts yet	2s	1024 MB	Judgeable
MetroGiven n cards with balances a_i and p extra burles to distribute, find the maximum number of metro rides at fee k per ride.	Medium5	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
Nested Candy BoxesGiven box counts a_i per nesting level, find the fewest boxes to open to collect at least x candies for each query.	Medium5	GreedySorting+2	No attempts yet	3s	1024 MB	Judgeable
Clean SocksGiven n socks with shades and a maximum allowed difference d, find the largest number of disjoint pairs whose shades differ by at most d.	Medium5	SortingGreedy	No attempts yet	2s	1024 MB	Judgeable
DDRGiven N dance steps that each need one or two arrows pressed in order, find the minimum total Euclidean distance both feet travel.	Medium5	Dynamic programmingImplementation	No attempts yet	2s	1024 MB	Judgeable
Gahee and the TunnelCount the length-s strings over 7 snack colors that contain red, orange, yellow, green, blue, navy, purple in that order as a subsequence, modulo 998244353.	Medium5	Dynamic programmingCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
Lexicographically Largest Common SubsequenceGiven two integer sequences A and B, find the lexicographically largest common subsequence and print its length and elements.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Sum of Intersection SizesGiven N sets, find for each k the sum of intersection sizes over all ways to pick k of the sets, modulo 998244353.	Medium5	CombinatoricsHash map	No attempts yet	4s	1024 MB	Judgeable
Subsequence MEXGiven a positive integer n with up to 200000 digits, find the smallest positive integer whose digits cannot be picked in order from n's digits.	Medium5	Dynamic programmingString+1	No attempts yet	1s	1024 MB	Judgeable
Fruitful cooperationGiven N up to 10^16, count the closed regions formed in the digits when all numbers from 1 to N are written in a row.	Medium5	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
Vasya and Cyclic ShiftsCount how many of a string's cyclic shifts equal its lexicographically smallest shift, for strings up to 10^7 characters long.	Medium5	StringString matching	No attempts yet	0.6s	1024 MB	Judgeable
A Million Scarlet RosesCount the distinct nonempty subsequences of a list of up to 1,000,000 bouquet sizes, modulo 1e9+7.	Medium5	Dynamic programmingArray+1	No attempts yet	1s	1024 MB	Judgeable
Reckless SpeleologistsFind the fastest route from the start station to the exit, reaching each station strictly before smoke spreading from the campfires does.	Medium5	GraphShortest path	No attempts yet	1s	1024 MB	Judgeable
XOR QueriesGiven an array with point updates, find the i-th largest value after XOR-ing every element with x, for each type 2 query.	Medium5	TrieBit manipulation	No attempts yet	2s	1024 MB	Judgeable