Problems

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Total results29,447 problems

Spy 2
Medium5
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Special Substring
Medium5
Sliding window, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Frequent Alphabet
Medium5
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Maximum Subset
Medium5
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Largest Exotic Number
Medium5
Sorting, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Inverse Common Superstring
Medium5
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Adding Numbers
Medium5
Dynamic programming, Math
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Coin Stacks
Medium5
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Exam Manipulation
Medium5
Brute force, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Triangular Collection
Medium5
Sorting, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Math Trade
Medium5
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Oreperations Research
Medium5
Dynamic programming, Prefix sum
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Restroom Monitor
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kangaroo Party
Medium5
Sorting, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Weird Flecks, But OK
Medium5
Geometry, Binary search+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Pulling Their Weight
Medium5
Sorting, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rounds
Medium5
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Interview Queue
Medium5
Linked list, Simulation
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Distance
Medium5
Math, Sorting+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Alias
Medium5
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Year of the Cow
Medium5
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Lexicographically Minimal Subsequence
Medium5
Stack, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Video Reviews - 2
Medium5
Greedy, Simulation
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
K Co-prime Permutation
Medium5
Number theory, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Let's Play Curling
Medium5
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hoseok's Two Chickens
Medium5
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cherimoyor
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rätblocket
Medium5
BFS, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Firewall
Medium5
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
ICPC Standings
Medium5
Sorting, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cheating
Medium5
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Robot Vacuum
Medium5
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Squirrel in the Tree
Medium5
Tree, DFS+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
3-i-rad
Medium5
Simulation, Game theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cutting Banknotes
Medium5
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Making Consecutive Primes
Medium5
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Long Number
Medium5
Math, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Digit Sum
Medium5
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Football Statistics
Medium5
Hash map, Implementation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fraction
Medium5
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Swamp 2
Medium5
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Candles
Medium5
Geometry, Hash map+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Oil
Medium5
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Wall
Medium5
Greedy, Array+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Space Invaders
Medium5
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chess Detective
Medium5
Brute force, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cinema
Medium5
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Triangular Frame
Medium5
Geometry, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Number
Medium5
String, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Automatic Friends
Medium5
Hash map, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cinema Academy
Medium5
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dice
Medium5
Math, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Stone Toy
Medium5
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Moving the Light Stone
Medium5
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Round Table
Medium5
Greedy, String+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
New Year Dinner
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Beautiful Sequence
Medium5
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Morning Walk
Medium5
Tree, DFS+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Shark Elementary School
Medium5
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Arranging Books
Medium5
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Walk of Three
Medium5
Graph, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Wheel of Fortune
Medium5
Math, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Text Formatting
Medium5
String, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Archery Championship
Medium5
Array, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Diplomas
Medium5
Binary search, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dance School
Medium5
Prefix sum, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Lucky Digits
Medium5
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Polyomino
Medium5
Matrix, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rolling a Snowball
Medium5
Dynamic programming, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dodo's Math Game
Medium5
Sorting, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Histogram
Medium5
Implementation, Array+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bingo
Medium5
Implementation, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Three Slices
Medium5
Binary search, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gahui and Log Files
Medium5
Binary search, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Typos
Medium5
Hash map, String
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Acowdemia I
Medium5
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Acowdemia II
Medium5
Graph, Topological sort
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Border Restrictions
Medium5
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Bubbles
Medium5
Union-find, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
__builtout_popcount
Medium5
Bit manipulation, Divide and conquer
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Innome
Medium5
Math, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Undergraduate Researcher Minsang
Medium5
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
City Construction
Medium5
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Secrets of Legendary Treasure
Medium5
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Problem Recommendation System Version 1
Medium5
Heap, Hash map+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Maximize the Expression
Medium5
Brute force, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Build It on a Foundation Stone
Medium5
Sliding window, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Splitting a Hexadecimal String
Medium5
Dynamic programming, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
ASCII Automata Art
Medium5
Implementation, Recursion+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Shopping Fever
Medium5
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Automatic Sprayer
Medium5
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Coin Collection
Medium5
Dynamic programming, Simulation
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Slot Machines
Medium5
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Game
Medium5
Dynamic programming, Probability+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Problem Review
Medium5
Dynamic programming, Implementation+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Round Number
Medium5
Greedy, Implementation+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Changyoung and the Jump
Medium5
Two pointers, Sliding window+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Two Towers
Medium5
Binary search, Implementation+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Alien Message
Medium5
Combinatorics, String+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Splitting Integers into Arrays
Medium5
Array, Math+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Spy 2Given each member's spy status and interview testimonies, decide whether the constraints are consistent and output a spy or non-spy label for every member.	Medium5	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
Special SubstringGiven a string and K, find the fewest character changes needed so some window of K consecutive characters becomes a single repeated letter.	Medium5	Sliding windowString+2	No attempts yet	1s	512 MB	Judgeable
Frequent AlphabetGiven two length-N strings S and T, choose one character from each column to maximize the count of the most frequent letter in the resulting password.	Medium5	GreedyMath+2	No attempts yet	1s	512 MB	Judgeable
Maximum SubsetGiven N integers, pick K of them to maximize the smallest gap between any two chosen values; duplicates make the gap zero.	Medium5	Binary searchGreedy+2	No attempts yet	1s	512 MB	Judgeable
Largest Exotic NumberGiven an N by N matrix, find the largest value that appears at two distinct cells where one cell is up and to the left of the other, or print -1 if none exists.	Medium5	SortingMatrix+2	No attempts yet	1s	512 MB	Judgeable
Inverse Common SuperstringGiven a string R, print the lexicographically smallest non-empty lowercase string that does not appear as a substring of R.	Medium5	StringHash map+2	No attempts yet	1s	512 MB	Judgeable
Adding NumbersGiven an array B of N integers, decide whether it can be built from all zeros by repeatedly adding (1,2) or (2,1) to two adjacent cells.	Medium5	Dynamic programmingMath	No attempts yet	0.5s	512 MB	Judgeable
Coin StacksGiven n coin stacks, repeatedly remove one coin from two different nonempty stacks; decide if all coins can be removed and print a valid sequence of moves.	Medium5	GreedyImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Exam ManipulationGiven n students' True/False answer strings of length k, choose an answer key to maximize the minimum score across all students.	Medium5	Brute forceBit manipulation+2	No attempts yet	1s	512 MB	Judgeable
Triangular CollectionCount subsets of at least three distinct positive integers in which every triple forms a valid triangle, given n up to 50.	Medium5	SortingTwo pointers+2	No attempts yet	1s	512 MB	Judgeable
Math TradeEach person has one item and wants one other item; find the longest chain of trades where each item passes to the next person.	Medium5	GraphDFS+2	No attempts yet	1s	1024 MB	Judgeable
Oreperations ResearchGiven two queues of ore carts and the capacities of train cars, decide whether whole-cart dumps can fill every car to exactly its capacity.	Medium5	Dynamic programmingPrefix sum	No attempts yet	7s	1024 MB	Judgeable
Restroom MonitorDecide whether all n people can use one of s stalls before their deadlines, when at most one toilet paper user may be inside at any time unit.	Medium5	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Kangaroo PartyGiven n distinct house positions, pick two of them as party houses so the sum of squared distances from every house to its nearest party house is minimized.	Medium5	SortingBrute force+2	No attempts yet	1s	512 MB	Judgeable
Weird Flecks, But OKGiven 3D points in a cube, find the smallest drill diameter so a bit entering perpendicular to a face removes all points, i.e. the smallest enclosing circle of the points projected onto each of the three coordinate planes.	Medium5	GeometryBinary search+2	No attempts yet	3s	1024 MB	Judgeable
Pulling Their WeightFind the smallest integer threshold t that splits the animal weights into two groups of equal total weight, with ties at t handled by pairing.	Medium5	SortingPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
RoundsEach round, every member except member i gives S credits to member i; after any round the outcome is the minimum holding, and we want the largest such minimum.	Medium5	GreedyMath+2	No attempts yet	1s	512 MB	Judgeable
Interview QueueGiven candidate values in a queue, repeatedly remove every candidate with a strictly larger neighbor, and report the minutes, the values removed each minute, and the final queue.	Medium5	Linked listSimulation	No attempts yet	4s	1024 MB	Judgeable
DistanceGiven N points on a grid, compute the sum of Manhattan distances over all distinct pairs.	Medium5	MathSorting+2	No attempts yet	3s	1024 MB	Judgeable
AliasGiven a weighted directed graph of n words and m edges, answer q queries asking the earliest time word b is reached after word a is spoken, or report that it never happens.	Medium5	GraphShortest path+2	No attempts yet	1s	512 MB	Judgeable
Year of the CowGiven N statements relating each new cow's birth year to an earlier cow by the nearest zodiac year before or after, find how many years apart Bessie and Elsie were born.	Medium5	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Lexicographically Minimal SubsequenceGiven a string s and an integer k, output the lexicographically smallest length-k subsequence of s.	Medium5	StackGreedy+2	No attempts yet	2s	512 MB	Judgeable
Video Reviews - 2Given n bloggers whose thresholds a_i come from piecewise linear congruential generators, find the fewest bloggers to convince so that at least m reviews appear.	Medium5	GreedySimulation	No attempts yet	4s	512 MB	Judgeable
K Co-prime PermutationGiven n and k, construct a permutation of 1 to n where exactly k indices i satisfy gcd(p_i, i) = 1, or report -1 if none exists.	Medium5	Number theoryImplementation	No attempts yet	1s	512 MB	Judgeable
Let's Play CurlingGiven red and blue stone positions on a line, find a center point c that maximizes how many red stones are strictly closer to c than every blue stone, or report Impossible.	Medium5	SortingGreedy+2	No attempts yet	1s	512 MB	Judgeable
Hoseok's Two ChickensChoose two buildings in an undirected graph to place shops so that the sum over all buildings of twice the distance to the nearest shop is minimized, breaking ties lexicographically.	Medium5	GraphShortest path+2	No attempts yet	1s	512 MB	Judgeable
CherimoyorEach day C_i cherimoyas become edible and stay edible for 3 days; eating the k-th fruit in a day gives 11-k points (max 10 per day). Maximize total enjoyment.	Medium5	Dynamic programmingGreedy	No attempts yet	1s	512 MB	Judgeable
RätblocketFind the fewest rolls that move a 1x1x2 block from cell A to cell B on a grid with blocked cells, modulo cells, and switch cells.	Medium5	BFSSimulation	No attempts yet	1s	512 MB	Judgeable
FirewallSimulate a rule list where each packet is checked top to bottom against port, IP, and a rate limit over the last 1000 packets, printing the action for every matching rule until accept or drop.	Medium5	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
ICPC StandingsScore ICPC contest submissions using standard rules (solved count, penalty time, tie-breakers) and print the top NR teams with their ranks.	Medium5	SortingImplementation+2	No attempts yet	1s	512 MB	Judgeable
CheatingGuess a hidden 4-letter lowercase password within 50 wrong attempts, using the count of correct-position and wrong-position letters reported after each guess.	Medium5	Brute forceImplementation	No attempts yet	1s	1024 MB	Judgeable
Robot VacuumA robot slides in each commanded direction until a box stops it; count the distinct grid cells it visits, including the start.	Medium5	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
The Squirrel in the TreeGiven a tree rooted at node 1 and a set of nodes holding nuts, find the shortest round trip from node 1 that visits every nut node.	Medium5	TreeDFS+2	No attempts yet	4s	1024 MB	Judgeable
3-i-radPlay tic-tac-toe interactively against an opponent, reading the board after each of their moves and printing your move; end the game once either side wins or draws.	Medium5	SimulationGame theory+2	No attempts yet	1s	1024 MB	Judgeable
Cutting BanknotesGiven a target amount in cents and a set of banknote values, decide whether some subset of notes can be split into halves repeatedly so the resulting pieces sum exactly to the target.	Medium5	MathNumber theory+2	No attempts yet	1s	1024 MB	Judgeable
Making Consecutive PrimesGiven n integers, change each into a prime so the chosen primes form a contiguous block of the prime sequence, minimizing the total change.	Medium5	SortingGreedy+1	No attempts yet	1s	512 MB	Judgeable
Long NumberFind the c-th digit of the number formed by concatenating the arithmetic sequence a, a+b, a+2b, ... with no separators.	Medium5	MathBinary search+2	No attempts yet	1s	512 MB	Judgeable
Digit SumSplit A into two non-negative integers B and C with sum A so that their digit sums total as much as possible, then print that maximum and the split.	Medium5	Dynamic programmingMath	No attempts yet	2s	1024 MB	Judgeable
Football StatisticsProcess a stream of football match records and queries, maintaining per-team and per-player goal statistics, minutes of goals, and score-opening counts.	Medium5	Hash mapImplementation+2	No attempts yet	2s	1024 MB	Judgeable
FractionGiven n, find the largest proper fraction whose numerator and denominator are coprime and sum to n.	Medium5	Number theoryMath+2	No attempts yet	2s	1024 MB	Judgeable
Swamp 2Find a path of jumps of size 1 or 2 that starts at leaf a, ends at leaf b, and visits every leaf exactly once, or report 0.	Medium5	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
CandlesGiven n candle points inside a circle and m lines that cut the cake, decide whether some region bounded by the lines contains two or more candles.	Medium5	GeometryHash map+2	No attempts yet	2s	1024 MB	Judgeable
OilGiven dollars and euros and n countries that each sell oil for a fixed dollar price or a fixed euro price, find the maximum barrels buyable when each country must be paid in a single currency.	Medium5	GreedySorting+2	No attempts yet	2s	1024 MB	Judgeable
WallGiven column heights, find the minimum number of moves of taking a top block to an adjacent column so that all heights differ by at most one.	Medium5	GreedyArray+2	No attempts yet	2s	1024 MB	Judgeable
Space InvadersGiven aliens stacked in n columns and a cannon starting at column p, find the minimum number of move and fire actions to destroy every alien.	Medium5	Dynamic programmingGreedy+2	No attempts yet	2s	1024 MB	Judgeable
Chess DetectiveDecide whether a grayed photo fragment can be part of a chessboard, and if so, replace each gray pixel with black or white.	Medium5	Brute forceImplementation	No attempts yet	2s	1024 MB	Judgeable
CinemaChildren fill an n by m hall row by row, then column by column. Count how many children end up in the same seat under both orders.	Medium5	MathNumber theory+2	No attempts yet	2s	1024 MB	Judgeable
Triangular FrameGiven a triangle with sides a, b, c and a frame width d, find the area of the triangular frame left after cutting out the inner triangle formed by moving each side inward by d.	Medium5	GeometryMath+2	No attempts yet	2s	1024 MB	Judgeable
NumberGiven several digit strings (the pieces), arrange all of them in some order to form the largest possible number and print it.	Medium5	StringSorting+2	No attempts yet	2s	1024 MB	Judgeable
Automatic FriendsCount pairs of triples that agree in exactly one coordinate and differ in the other two.	Medium5	Hash mapCombinatorics+2	No attempts yet	2s	1024 MB	Judgeable
Cinema AcademyChoose two different films to win best directing and best screenplay so that the total delight, where each film contributes one of three values depending on its outcome, is maximized.	Medium5	GreedyArray+2	No attempts yet	1s	1024 MB	Judgeable
DiceGiven the first player's total from rolling some six-sided dice, find the minimum and maximum possible total on the bottom faces.	Medium5	MathGreedy+2	No attempts yet	2s	1024 MB	Judgeable
Magic Stone ToySort a permutation of 1..N into increasing order using at most 100 reversals of adjacent segments, or report impossible.	Medium5	SortingGreedy+2	No attempts yet	1s	256 MB	Judgeable
Moving the Light StonePick drag or carry for each of N segments, paying a switch cost K whenever the choice changes, to minimize the total.	Medium5	Dynamic programmingGreedy+2	No attempts yet	1s	256 MB	Judgeable
Round TableArrange m boys and n girls in a circle to maximize how many people have the neighbor pattern that makes them active, and output one such seating.	Medium5	GreedyString+2	No attempts yet	2s	1024 MB	Judgeable
New Year DinnerGiven k and the sequence of remaining order counts n_1 to n_m, find the initial number of options for each of the k dish types.	Medium5	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Beautiful SequenceGiven N, print a sequence of N ones and N minus ones that maximizes the final value B_N of the recurrence B_i = B_(i-1) * A_(2i-1) + A_(2i).	Medium5	GreedyMath+1	No attempts yet	1s	256 MB	Judgeable
Morning WalkGiven a tree where each vertex is indoor or outdoor, count ordered pairs of distinct indoor vertices whose tree path has no other indoor vertex.	Medium5	TreeDFS+2	No attempts yet	3s	256 MB	Judgeable
Shark Elementary SchoolSeat students one by one in an N x N grid, choosing each seat by liking-adjacency, then empty-adjacency, then row and column, and sum the resulting satisfaction scores.	Medium5	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Arranging BooksGiven a string of L, M, and S characters, find the minimum number of swaps of two characters needed so that all L come first, then all M, then all S.	Medium5	GreedyString+2	No attempts yet	1s	1024 MB	Judgeable
Walk of ThreeCount walks of exactly three edges that start at vertex 1 and end at a neighbor of vertex 1 in a simple undirected graph.	Medium5	GraphCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Wheel of FortuneGiven n sector values on a circular wheel, a slowdown k per boundary crossing, and an initial velocity in [a, b], find the largest sector value the arrow can stop on when spinning either direction.	Medium5	MathImplementation+2	No attempts yet	2s	512 MB	Judgeable
Text FormattingReformat a text into paragraphs, each indented by b spaces and wrapped greedily at width w, with punctuation glued to the preceding word.	Medium5	StringSimulation+2	No attempts yet	2s	512 MB	Judgeable
Archery ChampionshipGiven a sequence of scores, find the best possible place of a participant whose score ends in 5, has a champion before him, and is followed immediately by a lower score.	Medium5	ArrayImplementation+2	No attempts yet	2s	512 MB	Judgeable
DiplomasGiven n identical w by h rectangles, find the smallest square side length that can contain all of them without overlaps.	Medium5	Binary searchMath+2	No attempts yet	2s	512 MB	Judgeable
Dance SchoolGiven a string of 'a' and 'b' of length up to 10^6, count the substrings in which the number of a's equals the number of b's.	Medium5	Prefix sumHash map+2	No attempts yet	2s	512 MB	Judgeable
Lucky DigitsGiven n and k, find a base d of at least 2 in which n ends with the most copies of digit k, then report d and that count of trailing k digits.	Medium5	Number theoryMath	No attempts yet	2s	512 MB	Judgeable
PolyominoCount the translations that fit the new polyomino entirely inside the old one with each cell split into K by K subcells, with no rotations or reflections.	Medium5	MatrixImplementation	No attempts yet	2s	1024 MB	Judgeable
Rolling a SnowballStarting with size 1 at position 0, each second either step +1 adding a[i+1] or jump +2 halving the size (floor) then adding a[i+2]; maximize the final size within M seconds.	Medium5	Dynamic programmingBrute force	No attempts yet	1s	1024 MB	Judgeable
Dodo's Math GameGiven N numbers, order and concatenate them so that the 180-degree rotated result is as large as possible, then print that value.	Medium5	SortingString+1	No attempts yet	2s	1024 MB	Judgeable
HistogramCount occurrences of each non-whitespace character in a text and print a vertical histogram of # bars sorted by character code.	Medium5	ImplementationArray+2	No attempts yet	2s	1024 MB	Judgeable
BingoGiven n and k, decide whether exactly k filled cells in an n x n grid can avoid completing any full row, column, or diagonal, and print such a grid.	Medium5	ImplementationGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Three SlicesFind the largest M such that the array contains three consecutive blocks of length M, each with sum at most K.	Medium5	Binary searchPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Gahui and Log FilesGiven timestamped logs and queries with a time range and a minimum level, count how many logs in the range have level at least the threshold.	Medium5	Binary searchPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
TyposFor each checked word, count the dictionary words that become identical to it after removing at most one letter from each word.	Medium5	Hash mapString	No attempts yet	2s	64 MB	Judgeable
Acowdemia IGiven N papers with citation counts and a budget of L extra citations (each paper cited at most once), find the maximum achievable h-index.	Medium5	SortingGreedy+2	No attempts yet	1s	512 MB	Judgeable
Acowdemia IIGiven K author lists ordered by effort, determine for each pair of N lab members whether one is definitely more senior, using alphabetical tie-breaks.	Medium5	GraphTopological sort	No attempts yet	1s	512 MB	Judgeable
Border RestrictionsGiven N countries and which origins each country admits travellers from, find the week the virus reaches every country starting from the first listed, or 0 if it never arrives.	Medium5	GraphBFS+2	No attempts yet	1s	256 MB	Judgeable
BubblesEach person sits in one of P personal bubbles and one of W work bubbles, every personal bubble meets every work bubble in exactly one person; given infected bubbles, count infected people.	Medium5	Union-findGraph+2	No attempts yet	1s	256 MB	Judgeable
__builtout_popcountImplement a function that counts the 1 bits in a 65536-bit integer, using at most 20 single-bit value checks.	Medium5	Bit manipulationDivide and conquer	No attempts yet	1s	512 MB	Judgeable
InnomeGiven memory m and at most k windows, where the i-th tab in a window costs i megabytes, find the maximum total number of tabs.	Medium5	MathBinary search+2	No attempts yet	2s	512 MB	Judgeable
Undergraduate Researcher MinsangCount the cells reached by wind from all air conditioners on a grid where four object types redirect the wind.	Medium5	BFSSimulation+1	No attempts yet	1s	512 MB	Judgeable
City ConstructionGiven a connected weighted undirected graph, compute the total edge cost minus the cost of a minimum spanning tree, or -1 if the graph is disconnected.	Medium5	Minimum spanning treeUnion-find+2	No attempts yet	1s	512 MB	Judgeable
Secrets of Legendary TreasureTwo ascending sequences of distinct numbers from 1 to n+m are given with some entries erased to 0; restore any valid pair.	Medium5	GreedyArray+2	No attempts yet	1s	512 MB	Judgeable
Problem Recommendation System Version 1Maintain a set of problems with difficulty values under add, remove, and query commands that ask for the hardest or easiest problem with a tie-break on problem number.	Medium5	HeapHash map+2	No attempts yet	1s	512 MB	Judgeable
Maximize the ExpressionArrange N given positive integers with P addition and Q multiplication operators, in any order and with any parentheses, to maximize the result.	Medium5	Brute forceBacktracking+2	No attempts yet	1s	512 MB	Judgeable
Build It on a Foundation StoneFind the longest contiguous subarray whose maximum minus minimum is at most 2, given values from 1 to 10.	Medium5	Sliding windowTwo pointers+2	No attempts yet	1s	512 MB	Judgeable
Splitting a Hexadecimal StringGiven a hex string of length up to 15, count the ways to cut it into substrings whose hex values are non-decreasing.	Medium5	Dynamic programmingBrute force+2	No attempts yet	1s	512 MB	Judgeable
ASCII Automata ArtGiven a regular expression of letters, +, ?, *, and parentheses, print its automaton as an ASCII art box following the stated layout rules.	Medium5	ImplementationRecursion+1	No attempts yet	3s	512 MB	Judgeable
Shopping FeverGiven n prices and a discount rate q, split the items into purchases so the total paid is minimized, where any purchase of 3 or more items gives the cheapest item free.	Medium5	Dynamic programmingGreedy+2	No attempts yet	1s	512 MB	Judgeable
Automatic SprayerGiven the 8x8 yields after sprayers were placed, recover which plots hold a fertilizer sprayer, a herbicide sprayer, or nothing.	Medium5	Brute forceImplementation+2	No attempts yet	1s	512 MB	Judgeable
Coin CollectionGiven n cells that each gain a_i coins per second, find the most coins a character can collect in t seconds by staying or moving to an adjacent cell.	Medium5	Dynamic programmingSimulation	No attempts yet	3s	256 MB	Judgeable
Slot MachinesDecide whether some sequence of lamp on and off buttons turns all lamps from off into the target pattern, and print one such sequence if it exists.	Medium5	GreedyImplementation	No attempts yet	2s	256 MB	Judgeable
GameEach room has two corridors to the next level; a player always takes the shorter one and picks randomly on ties. Compute the expected total path length from the first level to the last.	Medium5	Dynamic programmingProbability+2	No attempts yet	2s	256 MB	Judgeable
Problem ReviewEach of m problems must be reviewed in order by a jury member willing to review it; switching reviewers costs c seconds, so find the minimum total time.	Medium5	Dynamic programmingImplementation+2	No attempts yet	2s	256 MB	Judgeable
Round NumberFor each query, decide whether removing exactly k digits from x can leave a number with no leading zeros that is divisible by 100, and if so print one such result.	Medium5	GreedyImplementation+2	No attempts yet	2s	256 MB	Judgeable
Changyoung and the JumpGiven gaps between N red blocks and a stride K, find the longest run of blocks he can step through using at most one jump over a too-large gap.	Medium5	Two pointersSliding window+2	No attempts yet	2s	512 MB	Judgeable
Two TowersGiven passages joining two towers at listed floors and different elevator speeds, find the minimum time to travel between two given offices.	Medium5	Binary searchImplementation+2	No attempts yet	2s	256 MB	Judgeable
Alien MessageGiven a string of a, b, and ?, count how many ways to replace ? yield a string that is not two identical halves, modulo 1e9+7.	Medium5	CombinatoricsString+2	No attempts yet	2s	256 MB	Judgeable
Splitting Integers into ArraysSplit the integers 1 to 3n into three arrays of length n so that a_i + b_i = c_i for every i, or report -1 if no split exists.	Medium5	ArrayMath+1	No attempts yet	2s	256 MB	Judgeable