Problems

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Total results29,476 problems

Kri String
Easy3
Prefix sum, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Palindrome in Some Base
Easy3
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Folding Code
Easy3
Geometry, Implementation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Almost an Anagram
Easy3
Hash map, String
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Rings of Saturn
Easy3
Union-find, Sorting
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Bobby's Bet
Easy3
Probability, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Geometry Darts
Easy3
Geometry, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
One sheep... two sheep...
Easy3
DFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Diligent Cryptographer
Easy3
String, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
LOL
Easy3
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Beads
Easy3
Segment tree
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Neurotic Network
Easy3
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Ruben Spawns
Easy3
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Abandon Ship
Easy3
Simulation, Hash map
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Battle Sheep
Easy3
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Birds on a Wire
Easy3
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Lifting Walls
Easy3
Brute force, Geometry
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Pub-lic Good
Easy3
DFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Peragrams
Easy3
Hash map, String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
FreeCell
Easy3
Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Numbers on a Tree
Easy3
Math, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Choosing Pizza Toppings
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Falling Mugs
Easy3
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Broken Vending Machine
Easy3
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Polling
Easy3
Hash map, Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Pink
Easy3
Hash map, String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hydraulic Arm
Easy3
Stack, Simulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Candy
Easy3
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Travel of Alphabets
Easy3
Backtracking, DFS+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Cell Counting
Easy3
Matrix, Implementation
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Hunger Games
Easy3
Dynamic programming
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
PIN Code Possibilities
Easy3
Dynamic programming, Combinatorics
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Bell Ringing
Easy3
Recursion, Implementation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Server Capacity Plan
Easy3
Sliding window, Intervals
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
2-SAT Satisfiability
Easy3
Brute force, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Max Heap
Easy3
Heap
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Absolute Value Heap
Easy3
Heap
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Ethel's Encryption
Easy3
Number theory, String+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Boolean Postfix
Easy3
Stack
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Contest Ranking
Easy3
Implementation, Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Covering an equilateral triangle
Easy3
Math, Geometry
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Best Buddies
Easy3
Sorting, Hash map
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Roots! Really?
Easy3
Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Dyeing Dice
Easy3
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Strfry
Easy3
Hash map, String
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Bitcoin Profits
Easy3
Sorting, Prefix sum
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Largest inscribed rectangle
Easy3
Math, Geometry
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
There is no place like 127.0.0.1
Easy3
Binary search, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Waiting for Change
Easy3
Simulation, Queue
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cornell Party
Easy3
Hash map, Sorting
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Cornell Party Retry
Easy3
Hash map
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
A Serious Reading Problem
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Safe Zone
Easy3
Dynamic programming, Combinatorics
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Spawn of Ungoliant
Easy3
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
ATM
Easy3
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Path Finding
Easy3
Graph, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Olympic Parade
Easy3
Hash map
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Counting Primes in a Range
Easy3
Number theory, Prefix sum
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Folding a Paper Stripe
Easy3
Simulation, Array
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Maximum Number of Divisors
Easy3
Number theory, Prefix sum
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Range Sum Queries
Easy3
Prefix sum
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Manhattan Power Failure
Easy3
Union-find, Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rummikub
Easy3
Implementation, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Owl and the Fox
Easy3
Math, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Conversation Log
Easy3
Hash map, Sorting
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Nimionese
Easy3
String, Simulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Milestone Counter
Easy3
Brute force, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Stock
Easy3
Greedy, Array
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Sum of Three Primes
Easy3
Number theory, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Card Set
Easy3
Hash map, String
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Buy Two Get One Free
Easy3
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Positive Con Sequences
Easy3
Math, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Morse Code
Easy3
Hash map, String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Compositions Missing a Sequence
Easy3
Dynamic programming, Combinatorics
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
ACM Contest Scoring
Easy3
Simulation, Hash map
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Game of Death
Easy3
Graph, Simulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Stepping Stones
Easy3
Math, Binary search
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Kick
Easy3
String matching, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Recruiting Teammates
Easy3
Brute force, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Footprints
Easy3
Simulation, Hash map
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Relief Supplies
Easy3
DFS, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Chicken Top N
Easy3
Simulation, Sorting
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Classy
Easy3
Sorting, String+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Complexity
Easy3
Hash map, Greedy
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Class Time
Easy3
Sorting
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Blur
Easy3
Simulation, Matrix+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
ASCII Addition
Easy3
Implementation, Matrix
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Physical Music
Easy3
Array, Sorting
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Space Junk
Easy3
Math, Geometry
No attempts yet
Time limit
4s
Memory limit
256 MB
Judgeable
Xedni Drawkcab
Easy3
String, Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sorting Points by Coordinates
Easy3
Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sorting Coordinates 2
Easy3
Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cards
Easy3
Hash map, Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Prime factorization
Easy3
Number theory
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Suffix Array
Easy3
Sorting, String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Range sum queries
Easy3
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Minho and Kangho
Easy3
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Segment and Point
Easy3
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Jumbled Communication
Easy3
Bit manipulation, Brute force
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Longest Decreasing Subsequence
Easy3
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Kri StringFind the length of the longest even-length contiguous substring of a digit string whose two halves have equal digit sums.	Easy3	Prefix sumBrute force	No attempts yet	1s	256 MB	Judgeable
Palindrome in Some BaseFor each N, decide whether its base B representation is a palindrome for some B from 2 to 64.	Easy3	MathBrute force+1	No attempts yet	1s	256 MB	Judgeable
Folding CodeThe program reflects each folded corner across its fold line to find the ticked box and lists the chosen answers per question.	Easy3	GeometryImplementation	No attempts yet	2s	256 MB	Judgeable
Almost an AnagramGiven two lowercase words, order them by length then alphabetically and report whether they are identical, anagrams, almost anagrams, or unrelated.	Easy3	Hash mapString	No attempts yet	2s	256 MB	Judgeable
Rings of SaturnFind every connected group of exactly seven people, sum the threat levels inside each group, and list them by total threat.	Easy3	Union-findSorting	No attempts yet	2s	256 MB	Judgeable
Bobby's BetDecide whether a bet pays off by computing the binomial chance of rolling at least R on at least X of Y rolls and comparing it to the odds W.	Easy3	ProbabilityCombinatorics+1	No attempts yet	2s	256 MB	Judgeable
Geometry DartsCount how many circles, rectangles, and triangles contain each of six dart throws and name Bob, Hannah, or Tied as the winner of each game.	Easy3	GeometryBrute force	No attempts yet	1s	256 MB	Judgeable
One sheep... two sheep...Count the groups of # cells connected up, down, left, or right in each test grid.	Easy3	DFSGraph+1	No attempts yet	1s	256 MB	Judgeable
The Diligent CryptographerThe program prints old for each input string that fits only a repeated permutation key, new for one that fits only a random key, and unknown otherwise.	Easy3	StringBrute force	No attempts yet	1s	256 MB	Judgeable
LOLFind the fewest insertions, replacements, and deletions that make each given word contain lol as a contiguous substring.	Easy3	Dynamic programmingString	No attempts yet	1s	256 MB	Judgeable
BeadsProcess point additions to boxes and answer range-sum queries in order for each game.	Easy3	Segment tree	No attempts yet	1s	256 MB	Judgeable
Neurotic NetworkEvaluate the weighted sum from the leaves to the root of a tree and print FREAK OUT for an even result, else the value modulo 1,000,000,007.	Easy3	TreeDynamic programming+1	No attempts yet	1s	256 MB	Judgeable
Ruben SpawnsPick the fewest minions whose combined work capacities reach the required workload W.	Easy3	GreedySorting	No attempts yet	1s	256 MB	Judgeable
Abandon ShipProcess each damage report in order and print the recalibrate, invert, divert, or abandon ship order for its category.	Easy3	SimulationHash map	No attempts yet	1s	256 MB	Judgeable
Battle SheepSimulate Alice and Bob's preplanned Battleship shots, granting another turn after each sinking, and list the sunk ships in order and the winner.	Easy3	SimulationImplementation	No attempts yet	1s	256 MB	Judgeable
Birds on a WireCount how many more birds can sit on a wire of length l when birds stay d apart and 6 cm from each pole.	Easy3	GreedySorting+1	No attempts yet	1s	256 MB	Judgeable
Lifting WallsChoose the fewest of up to 30 crane sites so that each of the four wall centers is within reach of a chosen crane.	Easy3	Brute forceGeometry	No attempts yet	1s	256 MB	Judgeable
Pub-lic GoodColor each site pub or house with the specified ordered depth-first search so every site neighbors an opposite color, or print Impossible.	Easy3	DFSGraph+1	No attempts yet	1s	256 MB	Judgeable
PeragramsGiven a lowercase string, find the fewest letters to delete so the remaining letters can be rearranged into a palindrome.	Easy3	Hash mapString	No attempts yet	1s	256 MB	Judgeable
FreeCellDecide whether a sorted pile of K cards can be moved using N free cells and M empty stacks.	Easy3	Math	No attempts yet	1s	256 MB	Judgeable
Numbers on a TreeGiven the height H and an L/R path from the root, compute the label of the reached node under bottom-up right-to-left numbering.	Easy3	MathBit manipulation	No attempts yet	1s	256 MB	Judgeable
Choosing Pizza ToppingsSimulate the given repair loop that flips one unfulfilled topping of the first unhappy friend until every friend has more than a third of wishes met.	Easy3	SimulationImplementation+1	No attempts yet	1s	256 MB	Judgeable
Falling MugsGiven D, find nonnegative integers n1 and n2 with n2 squared minus n1 squared equal to D, smallest n1 first, or report impossible.	Easy3	Number theoryMath	No attempts yet	1s	256 MB	Judgeable
Broken Vending MachinePress each snack position through its cheapest button and keep only the snacks whose market price beats that press cost.	Easy3	GreedyArray	No attempts yet	1s	256 MB	Judgeable
PollingCount the votes for each candidate and print the names with the most votes in alphabetical order.	Easy3	Hash mapSorting	No attempts yet	1s	256 MB	Judgeable
PinkThe program counts how many registered 44-letter chromosomes contain each ten-letter query as a contiguous block.	Easy3	Hash mapString	No attempts yet	1s	256 MB	Judgeable
Hydraulic ArmDecide whether each given box sequence can reach the right belt in increasing height using one shelf as a stack.	Easy3	StackSimulation	No attempts yet	1s	256 MB	Judgeable
CandyPack J candies using the fewest boxes by filling the largest capacity boxes first.	Easy3	GreedySorting	No attempts yet	1s	256 MB	Judgeable
Travel of AlphabetsCount all length-L walks on a letter grid and the distinct strings among them, discarding any word containing a, c, or m.	Easy3	BacktrackingDFS+1	No attempts yet	2s	256 MB	Judgeable
Cell CountingCount the isolated # pixels with no # neighbor in any of the eight directions in each grid.	Easy3	MatrixImplementation	No attempts yet	3s	256 MB	Judgeable
Hunger GamesChoose weapons within the sack weight limit to maximize total preference.	Easy3	Dynamic programming	No attempts yet	3s	256 MB	Judgeable
PIN Code PossibilitiesCount n-digit codes with leading zeros allowed whose digits add up to s for each test case.	Easy3	Dynamic programmingCombinatorics	No attempts yet	3s	256 MB	Judgeable
Bell RingingPrint all permutations of 1 to n in the recursive insertion order where bell n sweeps each row left to right or right to left.	Easy3	RecursionImplementation	No attempts yet	2s	256 MB	Judgeable
Server Capacity PlanGiven sorted request times, find the smallest server count so no server exceeds k concurrent 1000ms jobs.	Easy3	Sliding windowIntervals	No attempts yet	1s	256 MB	Judgeable
2-SAT SatisfiabilityDecide whether N boolean variables admit an assignment satisfying all M two-literal clauses.	Easy3	Brute forceBit manipulation	No attempts yet	1s	256 MB	Judgeable
Max HeapProcess N insert and pop-max operations on an initially empty max heap, printing the maximum or 0 when empty.	Easy3	Heap	No attempts yet	1s	256 MB	Judgeable
Absolute Value HeapProcess insert and pop-min-by-absolute-value operations on integers with a custom heap, printing 0 on empty pops.	Easy3	Heap	No attempts yet	1s	256 MB	Judgeable
Ethel's EncryptionRecover the plaintext by computing the Caesar shift a^b modulo 26 and moving each ciphertext letter back by that amount.	Easy3	Number theoryString+1	No attempts yet	1s	256 MB	Judgeable
Boolean PostfixEvaluate each postfix Boolean formula with AND, OR, XOR, and NOT using a stack and print 1 for true and 0 for false.	Easy3	Stack	No attempts yet	1s	256 MB	Judgeable
Contest RankingParse each team per-problem records, sum the weights of solved problems, and print teams ranked by points with ties sharing a rank.	Easy3	ImplementationSorting	No attempts yet	1s	256 MB	Judgeable
Covering an equilateral triangleGiven side lengths A and B with A divisible by B, compute the minimum number of side-B equilateral triangles that cover a side-A equilateral triangle.	Easy3	MathGeometry	No attempts yet	1s	256 MB	Judgeable
Best BuddiesSort all participants by last name then first name, split the order into consecutive triples, and print each queried person's two teammates.	Easy3	SortingHash map	No attempts yet	2s	256 MB	Judgeable
Roots! Really?Decide for each quadratic equation whether a real root lies inside the given closed interval.	Easy3	Math	No attempts yet	1s	256 MB	Judgeable
Dyeing DiceSimulate the die rolling along the given path, dye each bottom face on painted squares, and output the six face colors or zeros on failure.	Easy3	SimulationImplementation	No attempts yet	1s	256 MB	Judgeable
StrfryFor each pair of lowercase strings, decide whether the second is a rearrangement of the first.	Easy3	Hash mapString	No attempts yet	2s	256 MB	Judgeable
Bitcoin ProfitsGiven share difficulties, pick the integer k of at least 1 that maximizes k times the count of shares at or above k, breaking ties toward the smaller k.	Easy3	SortingPrefix sum	No attempts yet	2s	256 MB	Judgeable
Largest inscribed rectangleGiven radius R and bound B, find the largest area of a rectangle inscribed in the circle whose shorter side is at most B.	Easy3	MathGeometry	No attempts yet	2s	256 MB	Judgeable
There is no place like 127.0.0.1Replace each IPv4 address in the text with its mapped word from single entries and non-overlapping ranges, leaving unmatched addresses unchanged.	Easy3	Binary searchSorting+1	No attempts yet	2s	256 MB	Judgeable
Waiting for ChangeSimulate book sales across two queues with limited five-dollar change and report line B at its longest moment.	Easy3	SimulationQueue	No attempts yet	1s	256 MB	Judgeable
Cornell PartyDecide whether two arrival logs match up to a renaming of guests by comparing the multisets of visit counts.	Easy3	Hash mapSorting	No attempts yet	3s	256 MB	Judgeable
Cornell Party RetryCount distinct names across two guest lists to find the minimum party attendance.	Easy3	Hash map	No attempts yet	3s	256 MB	Judgeable
A Serious Reading ProblemGiven C, W, L and P per test case, print C raised to W times L times P in full, treating 0 to the 0 as 1.	Easy3	MathImplementation	No attempts yet	1s	256 MB	Judgeable
Safe ZoneCount the K-step walks on segments 0 to N-1 with forced turns at the ends that finish inside segments P to Q.	Easy3	Dynamic programmingCombinatorics	No attempts yet	1s	256 MB	Judgeable
Spawn of UngoliantSpiders spread to every tree connected by four-directional adjacency to an infested tree, and isolated trees and open floor stay unchanged.	Easy3	BFSGraph+1	No attempts yet	1s	256 MB	Judgeable
ATMReorder N people by withdrawal time so the sum of all waiting-plus-service finish times is as small as possible.	Easy3	GreedySorting+1	No attempts yet	1s	256 MB	Judgeable
Path FindingDecide for every ordered pair of vertices in a directed graph with up to 100 vertices whether a path of at least one edge connects them.	Easy3	GraphDynamic programming	No attempts yet	1s	256 MB	Judgeable
Olympic ParadeFind the ID that does not appear a multiple of K times among N given IDs.	Easy3	Hash map	No attempts yet	1s	256 MB	Judgeable
Counting Primes in a RangeCount the primes between m and n inclusive for each blank-line separated test case.	Easy3	Number theoryPrefix sum	No attempts yet	1s	256 MB	Judgeable
Folding a Paper StripeSimulate the K given half-folds of a 2^K-cell stripe and print the cell numbers from top to bottom.	Easy3	SimulationArray	No attempts yet	1s	256 MB	Judgeable
Maximum Number of DivisorsYou answer each query with the largest divisor count among integers from 1 to N that are not multiples of P.	Easy3	Number theoryPrefix sum	No attempts yet	1s	256 MB	Judgeable
Range Sum QueriesAnswer many range-sum queries over a static array by precomputing prefix sums and subtracting.	Easy3	Prefix sum	No attempts yet	1s	256 MB	Judgeable
Manhattan Power FailureCount the blocks linked by intact lines into regions and report how many regions hold no generator.	Easy3	Union-findGraph	No attempts yet	1s	256 MB	Judgeable
RummikubDecide whether a hand of numbered suit tiles contains a valid group or run of at least three tiles.	Easy3	ImplementationSorting+1	No attempts yet	1s	256 MB	Judgeable
The Owl and the FoxGiven N, find the largest integer below N whose digit sum is exactly one less than the digit sum of N.	Easy3	MathGreedy	No attempts yet	1s	256 MB	Judgeable
Conversation LogFind words used at least once by every user and list them by total frequency, breaking ties alphabetically.	Easy3	Hash mapSorting	No attempts yet	2s	256 MB	Judgeable
NimioneseEach word is rewritten by mapping its first letter to the nearest hard consonant, copying it over later hard consonants, and adding a vowel if it ends in one.	Easy3	StringSimulation	No attempts yet	1s	256 MB	Judgeable
Milestone CounterMatch the recorded pass times against milestone positions to count feasible speeds and list each possible first gap.	Easy3	Brute forceMath	No attempts yet	1s	256 MB	Judgeable
StockCompute the largest profit from daily prices when you may buy one share per day and sell any number of held shares on any day.	Easy3	GreedyArray	No attempts yet	5s	256 MB	Judgeable
Sum of Three PrimesRead each odd K between 7 and 999 and print the lexicographically smallest triple of primes summing to K, or 0.	Easy3	Number theoryBrute force	No attempts yet	1s	256 MB	Judgeable
Card SetSplit S into 3-character card names, print GRESKA if any card repeats, otherwise print the missing count out of 13 for suits P, K, H and T.	Easy3	Hash mapString	No attempts yet	1s	32 MB	Judgeable
Buy Two Get One FreeSort all prices from high to low and take every third pack free to pay the smallest possible total.	Easy3	GreedySorting	No attempts yet	1s	64 MB	Judgeable
Positive Con SequencesFill the missing entry of each four-term sequence with a number from 1 to 10000 that makes it arithmetic or geometric, or output -1.	Easy3	MathBrute force	No attempts yet	1s	256 MB	Judgeable
Morse CodeGiven a Morse table and a dictionary, match each gapless Morse code word to its dictionary word or report the first missing one.	Easy3	Hash mapString	No attempts yet	1s	256 MB	Judgeable
Compositions Missing a SequenceCount the ordered compositions of n that use no part from the arithmetic progression starting at m with step k.	Easy3	Dynamic programmingCombinatorics	No attempts yet	1s	256 MB	Judgeable
ACM Contest ScoringProcess the team's submission log in order and report the number of solved problems and the total penalty including 20 minutes per prior wrong attempt.	Easy3	SimulationHash map	No attempts yet	1s	256 MB	Judgeable
The Game of DeathStarting from player 1, follow the pointed-to players and report the first step that reaches player N, or 0 when it never does.	Easy3	GraphSimulation	No attempts yet	1s	256 MB	Judgeable
Stepping StonesMaximize the number of landed stones when jump lengths grow by at least one each time and the last landing is stone N.	Easy3	MathBinary search	No attempts yet	1s	256 MB	Judgeable
KickFind the shallowest and deepest depths at which the reality notes appear as an evenly spaced subsequence of the dream notes.	Easy3	String matchingBrute force	No attempts yet	1s	256 MB	Judgeable
Recruiting TeammatesPick the fewest of up to 10 students whose solvable problem sets cover all N problems, or print -1 when coverage is impossible.	Easy3	Brute forceBit manipulation	No attempts yet	2s	256 MB	Judgeable
FootprintsCount distinct grid cells visited when walking L steps from the origin following N, S, E, and W commands.	Easy3	SimulationHash map	No attempts yet	2s	256 MB	Judgeable
Relief SuppliesDecide whether any walk starting at intersection 1 in a directed graph can revisit an intersection.	Easy3	DFSGraph	No attempts yet	2s	256 MB	Judgeable
Chicken Top NPrint the row after one bottom-up merge sort stage by merging each pair of sorted groups of length N/(2k) into one sorted group of length N/k.	Easy3	SimulationSorting	No attempts yet	5s	256 MB	Judgeable
ClassySort people by refined class rank, treating missing levels as middle, breaking ties by name.	Easy3	SortingString+1	No attempts yet	2s	256 MB	Judgeable
ComplexityYou delete the fewest letters so at most two distinct letters remain.	Easy3	Hash mapGreedy	No attempts yet	2s	256 MB	Judgeable
Class TimeSort the student names by last name, breaking ties by first name, and print them in that order.	Easy3	Sorting	No attempts yet	2s	256 MB	Judgeable
BlurBlur a binary image up to nine times with a wrapping 3 by 3 average and count how many distinct gray values remain.	Easy3	SimulationMatrix+1	No attempts yet	2s	256 MB	Judgeable
ASCII AdditionRead the 7-row ASCII art of a plus b and print their sum in the same 7 by 5 digit art.	Easy3	ImplementationMatrix	No attempts yet	1s	512 MB	Judgeable
Physical MusicGiven a permutation of chart positions, list the download-chart positions of entries that a later single outranks, in ascending order.	Easy3	ArraySorting	No attempts yet	5s	256 MB	Judgeable
Space JunkTwo spheres drift on straight paths at constant speeds, and you compute the first instant their surfaces touch or report no collision.	Easy3	MathGeometry	No attempts yet	4s	256 MB	Judgeable
Xedni DrawkcabReverse each uppercase word and print the reversed words in alphabetical order.	Easy3	StringSorting	No attempts yet	1s	256 MB	Judgeable
Sorting Points by CoordinatesSort N planar points by increasing x coordinate, breaking ties by increasing y, and print them in order.	Easy3	Sorting	No attempts yet	1s	256 MB	Judgeable
Sorting Coordinates 2Sort N points by increasing y coordinate, breaking ties by increasing x, and print them.	Easy3	Sorting	No attempts yet	1s	256 MB	Judgeable
CardsCount the N card values and print the most frequent one, breaking ties by the smaller value.	Easy3	Hash mapSorting	No attempts yet	1s	256 MB	Judgeable
Prime factorizationPrint the prime factors of N up to 10,000,000 in ascending order, repeating each factor by multiplicity.	Easy3	Number theory	No attempts yet	1s	256 MB	Judgeable
Suffix ArrayGiven a lowercase string, print all of its suffixes in lexicographic order, one per line.	Easy3	SortingString	No attempts yet	1s	256 MB	Judgeable
Range sum queriesAnswer many inclusive range-sum queries over a fixed list by precomputing prefix sums.	Easy3	Prefix sumArray	No attempts yet	1s	256 MB	Judgeable
Minho and KanghoTwo people walk straight lines at constant speeds over the same time span, and the program prints the smallest distance between them to ten decimal places.	Easy3	GeometryMath	No attempts yet	1s	256 MB	Judgeable
Segment and PointFind the closest point on segment AB to point C in 3D and print the distance with ten decimals.	Easy3	GeometryMath	No attempts yet	1s	256 MB	Judgeable
Jumbled CommunicationRecover each original byte x from the scrambled value x xor (x shifted left by one).	Easy3	Bit manipulationBrute force	No attempts yet	5s	256 MB	Judgeable
Longest Decreasing SubsequenceFind the length of the longest strictly decreasing subsequence of the given sequence.	Easy3	Dynamic programming	No attempts yet	1s	256 MB	Judgeable