Problems

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Total results29,471 problems

Missing W Key
Easy3
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Minimax Tree
Easy3
Tree, DFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Swords
Easy3
Sorting, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Efficient Engine
Easy3
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Uninvited Guests (Basic)
Easy3
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Scary Numbers
Easy3
Math, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Scariest Story (Basic)
Easy3
Prefix sum, Binary search
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
In Search of Venom
Easy3
Number theory, Simulation
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Suspicious Reports (Basic)
Easy3
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Optimizing the Matrix
Easy3
Prefix sum, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Electronic Lock
Easy3
Greedy, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Xeroxinator
Easy3
Queue, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jaewoo, Get Commissioned
Easy3
Probability, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
FizzBuzz
Easy3
Implementation, Math
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Lucky Seven
Easy3
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Napor
Easy3
String, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Scissors
Easy3
Math, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crazy Transport Taxes
Easy3
Binary search, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bank Robbery
Easy3
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Typing Text
Easy3
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Counting Hashtags
Easy3
Hash map, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Secret Code
Easy3
Math, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Old Man and the Chessboard
Easy3
Math, Binary search
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bit Automatic Gun
Easy3
Bit manipulation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gathering the Followers
Easy3
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Nufflers
Easy3
Tree, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Solitaire
Easy3
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Safe Travel
Easy3
Graph, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gardening on the Train
Easy3
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cup Pyramids
Easy3
Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Princess Dungeon
Easy3
Array, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Shoe Cabinet
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Levitation Cloak
Easy3
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Message
Easy3
Greedy, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magical Creatures
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Search
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Batman and Robin
Easy3
Greedy, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Blade Tips
Easy3
Hash map, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Movie Outing
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Luigi's Calculations
Easy3
Math, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Recruits
Easy3
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mushrooms
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Spelling
Easy3
Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Peeta's Bow
Easy3
Array, Intervals
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Safe Password
Easy3
String, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Messenger in the Seven Kingdoms
Easy3
Simulation, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tic-Tac-Toe
Easy3
Matrix, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Genome
Easy3
Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Odd or Even?
Easy3
Math, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Run, Alf! Run!
Easy3
Dynamic programming, Matrix
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Alf and the Chalkboard
Easy3
Simulation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dima and the Construction Set
Easy3
Binary search, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rebellion
Easy3
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tab UI
Easy3
Prefix sum, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
SpongeBob's Book Collection
Easy3
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Balloons
Easy3
Hash map, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cubes
Easy3
Brute force, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Every pony can write
Easy3
Combinatorics, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Morning Taekwondo
Easy3
Hash map, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kolevskaya Bookkeeping
Easy3
Brute force, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Winter Supplies
Easy3
Sorting, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Poker
Easy3
Math, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Testing
Easy3
Array, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bumblebee's Malfunction
Easy3
Prefix sum, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
When are the holidays?
Easy3
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Split into X Parts
Easy3
Array, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hemoglobin
Easy3
Stack, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Palindromes
Easy3
String, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pod Racing
Easy3
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cipher
Easy3
String, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Conqueror
Easy3
Array, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hold the Line
Easy3
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Forks and Knives
Easy3
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sacred Number
Easy3
Greedy, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Winter Supplies
Easy3
Hash map, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Enemy of My Enemy Is My Friend!
Easy3
Graph, Hash map
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fraction Numbering
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
k-Sort
Easy3
Sorting, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Traffic Light Bulbs
Easy3
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Travelator
Easy3
Geometry, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Triangle
Easy3
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Traffic Jam
Easy3
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Elections
Easy3
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Blocks
Easy3
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Haircut
Easy3
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Satellite
Easy3
Sorting, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Photograph
Easy3
Implementation, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cipher
Easy3
String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Message
Easy3
Number theory, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Semi-Case-Insensitive Search
Easy3
Hash map, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cut!
Easy3
Implementation, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Deoxyribonucleic Acid
Easy3
String, String matching
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Wars of Planets
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Simple Problem
Easy3
Brute force, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Big Square Piece
Easy3
Sorting, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sneaky Parking Attendant
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Confession
Easy3
String, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dragon Teeth
Easy3
Array, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Potion of the Power of Numbers
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tours
Easy3
Sliding window, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Missing W KeyCount the empty starting cells from which the character can reach F on an N by N board using only the seven keys other than W.	Easy3	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
Minimax TreeGiven a rooted tree with known leaf values, compute the minimax value of each queried node, with the root as MAX and players alternating by depth.	Easy3	TreeDFS	No attempts yet	1s	1024 MB	Judgeable
SwordsCount the swords that no other sword matches or beats in both attack and defence.	Easy3	SortingArray	No attempts yet	1s	1024 MB	Judgeable
Efficient EngineGiven n, count the pocket universes that are functioning after n flights, where universe k changes state once for each of its divisors.	Easy3	MathNumber theory	No attempts yet	1s	1024 MB	Judgeable
Uninvited Guests (Basic)Given arrival and departure logs for each category, find the minimum number of distinct creatures per category that must have visited Earth.	Easy3	Prefix sumArray	No attempts yet	1s	1024 MB	Judgeable
Scary NumbersFor each query, count the integers in [l, r] whose prime factors, counted with multiplicity, number exactly k, with up to 1e5 queries.	Easy3	MathPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
The Scariest Story (Basic)Given a story of n words and m global character positions, print the word number and the character's position within that word for each position.	Easy3	Prefix sumBinary search	No attempts yet	1s	1024 MB	Judgeable
In Search of VenomGiven a rectangle with sides a and b, count how many squares of the shorter side are scanned until the whole territory is covered.	Easy3	Number theorySimulation	No attempts yet	0.5s	1024 MB	Judgeable
Suspicious Reports (Basic)Given a full report s and a pattern t, decide whether t is the upper slice of s at some level h, and output the matching column indices.	Easy3	Brute forceImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Optimizing the MatrixPick one node and spread its action k nodes in each direction, zeroing the reached nodes and multiplying the chosen one. Find the maximum total importance.	Easy3	Prefix sumImplementation	No attempts yet	1s	1024 MB	Judgeable
Electronic LockGiven at most n lit segments on a 7-segment display, print the largest natural number that can be shown.	Easy3	GreedyMath	No attempts yet	2s	1024 MB	Judgeable
XeroxinatorGiven each minute's arrivals and a per-minute service limit b, compute the total minutes all clones spend in the post office queue over n minutes.	Easy3	QueueSimulation	No attempts yet	2s	1024 MB	Judgeable
Jaewoo, Get CommissionedJaewoo picks one course, the professor reveals a failing course among the other two, and he must choose the remaining course so that at least 900 of 1500 worlds end in a pass.	Easy3	ProbabilityImplementation	No attempts yet	1s	1024 MB	Judgeable
FizzBuzzGiven three consecutive FizzBuzz outputs, print the string that comes right after them.	Easy3	ImplementationMath	No attempts yet	0.5s	1024 MB	Judgeable
Lucky SevenStarting from K=1, each of N turns offers two operations (add or multiply by a digit 1 to 9). Decide whether K can end as a multiple of 7.	Easy3	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
NaporExtract every run of digits from n lines of letters and digits, strip leading zeros, and print the numbers sorted in non-decreasing order.	Easy3	StringSorting	No attempts yet	1s	1024 MB	Judgeable
ScissorsFind the total length of the grid-line cuts for an inward spiral on an n by m sheet that never splits the paper.	Easy3	MathSimulation	No attempts yet	2s	1024 MB	Judgeable
Crazy Transport TaxesGiven a step-function rate table and a list of car powers, print each car's tax, which is the matching band's rate times the power.	Easy3	Binary searchArray	No attempts yet	2s	1024 MB	Judgeable
Bank RobberyCount the length-n lock codes over letters a to z whose first letter and adjacent letter gaps match the hint, modulo 1000000007.	Easy3	Dynamic programming	No attempts yet	2s	1024 MB	Judgeable
Typing TextGiven a string typed on a QWERTY keyboard, find the fewest key presses when holding shift can cover several characters at once.	Easy3	Dynamic programmingImplementation	No attempts yet	2s	1024 MB	Judgeable
Counting HashtagsCount the distinct hashtags in a text, where a hashtag is a space-separated word that starts with # and has no other #, then print each with its occurrence count.	Easy3	Hash mapString	No attempts yet	2s	1024 MB	Judgeable
Secret CodeGiven a string, count the distinct strings that result from exactly one swap of two characters at different positions.	Easy3	MathString+1	No attempts yet	2s	1024 MB	Judgeable
The Old Man and the ChessboardGiven n white and m black unit squares, find the largest side length of a checkered square board that can be built from them.	Easy3	MathBinary search	No attempts yet	2s	1024 MB	Judgeable
Bit Automatic GunGiven n fired bits and an observed damage a, find the minimum and maximum real damage if Ralph misread the outcome of at most one bit.	Easy3	Bit manipulationMath	No attempts yet	2s	1024 MB	Judgeable
Gathering the FollowersGiven each follower's visit period d_i and the weekday s of the last joint meeting, find the weekday of the next joint meeting.	Easy3	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
NufflersGiven a tree of n boxes, find the minimum number of edges between two distinct leaves (dead ends).	Easy3	TreeBFS+1	No attempts yet	2s	1024 MB	Judgeable
SolitaireFind the length of the longest subsequence of the cards that is strictly increasing and alternates between even and odd numbers.	Easy3	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
Safe TravelGiven n planets and m paths, build a graph where a walk from start p visits every planet and returns to p, or report Impossible.	Easy3	GraphImplementation	No attempts yet	2s	1024 MB	Judgeable
Gardening on the TrainGiven n plants with growth times a_i, plant one per day to minimize the day when the last plant ripens.	Easy3	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
Cup PyramidsGiven an N by M base of cups, find the total cup count of a pyramid where each level shrinks by one row and one column until no level fits.	Easy3	Math	No attempts yet	3s	1024 MB	Judgeable
Princess DungeonFor each raid, pick the empty cell with the smallest capacity at least b_j, breaking ties by distance to the entrance, and print its number or -1.	Easy3	ArraySimulation	No attempts yet	2s	1024 MB	Judgeable
Shoe CabinetCount the shoe pairs for which no person height satisfies both the shelf height range and the shoe size range.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Levitation CloakGiven a clothesline of height h and length l, and a cloak of sides a and b, decide whether the cloak can be draped over the line without touching the floor.	Easy3	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
MessageGiven strings c and s, find the largest k such that c repeated k times is a subsequence of s.	Easy3	GreedyString	No attempts yet	2s	1024 MB	Judgeable
Magical CreaturesCount how many terms of the sequence t, t+s, t+2s, ... fall inside each interval [a_i, b_i], then print the total over all intervals.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
SearchGiven a string of L and R moves with unknown positive integer lengths from coordinate 0, decide whether the final position can be x.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Batman and RobinGiven a sequence, find the largest alternating sum a1 - a2 + a3 - ... that can be reached by swapping at most one pair of elements.	Easy3	GreedyArray	No attempts yet	2s	1024 MB	Judgeable
Blade TipsGiven n tips with values x and y, find the largest subset where every x+y sum is distinct, which is the count of distinct sums.	Easy3	Hash mapImplementation	No attempts yet	2s	1024 MB	Judgeable
Movie OutingGiven an odd-sized N by N hall with Chico in the center, count the maximum number of friends who can sit at least A rows and B seats away from him.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Luigi's CalculationsGiven tire range [A, B], rim range [C, D], and divisor k, find x and y with x + y divisible by k and the largest possible sum, or report -1.	Easy3	MathGreedy	No attempts yet	1s	1024 MB	Judgeable
RecruitsCount the commands after which a row of carts, where recruits swap Left and Right, has carts facing different directions.	Easy3	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
MushroomsGiven the mushroom totals for ten pairwise races among five people, decide whether some non-negative integer count per person fits all ten totals.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
SpellingGiven an uppercase string, find the minimum total number of pen lifts needed to write it, using a fixed lift count per letter.	Easy3	Implementation	No attempts yet	2s	1024 MB	Judgeable
Peeta's BowGiven n hints as intervals [x_i - d_i, x_i + d_i], find the largest point X inside all of them, or report -1 if no such point exists.	Easy3	ArrayIntervals	No attempts yet	2s	1024 MB	Judgeable
Safe PasswordGiven a lowercase string, decide whether swapping at most two characters can turn it into a palindrome.	Easy3	StringImplementation	No attempts yet	2s	1024 MB	Judgeable
Messenger in the Seven KingdomsFor each starting city, the messenger always moves to the nearest unvisited city, and the task asks for the smallest total squared distance over all starts.	Easy3	SimulationBrute force	No attempts yet	2s	1024 MB	Judgeable
Tic-Tac-ToeGiven an n by m board of X, O, and empty cells, the task is to check whether any row, column, or diagonal has five identical marks in a row.	Easy3	MatrixImplementation	No attempts yet	2s	1024 MB	Judgeable
GenomeGiven starting counts of genes X, Y, Z and a number k of catalyst steps, print how many more X genes than Y genes remain after k steps.	Easy3	Math	No attempts yet	2s	1024 MB	Judgeable
Odd or Even?Given the parities of x and y, decide whether the arithmetic expression string evaluates to an odd or even number.	Easy3	MathString	No attempts yet	2s	1024 MB	Judgeable
Run, Alf! Run!Find the most coins Alf can collect on an n by 3 grid, moving down one row at a time diagonally or straight while avoiding walls.	Easy3	Dynamic programmingMatrix	No attempts yet	2s	1024 MB	Judgeable
Alf and the ChalkboardStarting from n, each minute adds the number's last digit to it. Find the number on the board after k minutes.	Easy3	SimulationMath	No attempts yet	2s	1024 MB	Judgeable
Dima and the Construction SetGiven n stack heights a_i and k extra pieces, find the largest h such that every stack can be raised to at least h.	Easy3	Binary searchGreedy	No attempts yet	2s	1024 MB	Judgeable
RebellionFor each squad, pick the cheapest worker whose wage is at least half the squad's total, then print the sum of those wages or -1 if some squad has none.	Easy3	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
Tab UIGiven tab lengths, a screen length, and a sequence of clicks, print the tab row's position after each click, clamped to the scroll limits.	Easy3	Prefix sumImplementation	No attempts yet	1s	1024 MB	Judgeable
SpongeBob's Book CollectionAfter each swap of two shelf positions, count how many books numbered 1 to n sit in the first n positions of a shelf holding 2n books.	Easy3	ArrayImplementation	No attempts yet	2s	1024 MB	Judgeable
BalloonsPick k of the n balloons so that the chosen set contains as many distinct colors as possible, then print their colors.	Easy3	Hash mapGreedy	No attempts yet	2s	1024 MB	Judgeable
CubesGiven n tower heights, find the minimum number of move, add, or remove actions that make all towers the same height.	Easy3	Brute forceImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Every pony can writeCount the distinct strings of length n that can be built from the given string s, printed modulo 1e9+7.	Easy3	CombinatoricsString+1	No attempts yet	2s	1024 MB	Judgeable
Morning TaekwondoCount the students visible from the origin, where a student is hidden if another student lies on the segment from the origin to that student.	Easy3	Hash mapMath	No attempts yet	1s	1024 MB	Judgeable
Kolevskaya BookkeepingGiven current antelope, zebra, and remains counts, count the earlier states where antelopes outnumbered zebras and every eaten animal became one unit of remains.	Easy3	Brute forceMath	No attempts yet	2s	1024 MB	Judgeable
Winter SuppliesPick the most time intervals [l_i, r_i] so that each one ends no later than the next one starts, and print their order.	Easy3	SortingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
PokerGiven Loki's money and the small blind, count the rounds until Loki runs out when he folds every time and the blinds swap after each round.	Easy3	MathSimulation	No attempts yet	2s	1024 MB	Judgeable
TestingGiven n cards that each hold two different numbers from 1 to n+1, find the fewest cards to change so that one number appears on every card.	Easy3	ArrayHash map+1	No attempts yet	2s	1024 MB	Judgeable
Bumblebee's MalfunctionFor each query segment of an array, output the gcd of the mex values over all nonempty subsets of that segment.	Easy3	Prefix sumImplementation	No attempts yet	2s	1024 MB	Judgeable
When are the holidays?Given the weekday of January 1 and whether the year is leap, find the day of the month for each holiday defined as the first or last given weekday of a month.	Easy3	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
Split into X PartsSplit an array of n numbers into X consecutive non-empty parts so each part's sum is at least b_j, minimizing the total excess over the thresholds.	Easy3	ArrayPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
HemoglobinProcess a stream of push, pop, and last-k sum queries on a stack of patient hemoglobin levels, printing each popped value and each requested sum.	Easy3	StackPrefix sum	No attempts yet	2s	1024 MB	Judgeable
PalindromesGiven a string and one-time letter replacement rules, find the fewest replacements that make the string a palindrome, or report -1.	Easy3	StringImplementation	No attempts yet	2s	1024 MB	Judgeable
Pod RacingGiven the finishing order of n cars, find every k such that the first k finishers are exactly cars 1 through k.	Easy3	ArrayImplementation	No attempts yet	1s	1024 MB	Judgeable
CipherCount the lengths k for which the prefix and suffix of length k contain the same nonzero number of vowels, with uppercase vowels included.	Easy3	StringPrefix sum	No attempts yet	2s	1024 MB	Judgeable
ConquerorGiven the horse speed at each of n cities on a line, find the minimum time for a rider to reach the last city, switching horses at any city he has passed.	Easy3	ArrayGreedy	No attempts yet	2s	1024 MB	Judgeable
Hold the LineEach update replaces the height at one position, and each query asks whether the whole line is in non-decreasing order.	Easy3	ArrayImplementation	No attempts yet	2s	1024 MB	Judgeable
Forks and KnivesFor each visitor in arrival order, decide whether enough forks and knives are free when they arrive, given their stay length and whether they order the second course.	Easy3	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Sacred NumberGiven a natural number n up to 100, output at most 50 operations (subtract 1 or multiply by 2) that turn n into 1000.	Easy3	GreedyMath	No attempts yet	2s	1024 MB	Judgeable
Winter SuppliesGiven the signed jar numbers left after one jar vanished, find the number on the missing jar, where each absolute value must appear equally often with each sign.	Easy3	Hash mapMath	No attempts yet	2s	1024 MB	Judgeable
The Enemy of My Enemy Is My Friend!Given directed enemy edges added online, count users who are an enemy of an enemy of v, excluding v itself and v's direct enemies.	Easy3	GraphHash map	No attempts yet	2s	1024 MB	Judgeable
Fraction NumberingGiven n up to 10^18, find the numerator and denominator of the n-th fraction in the zigzag diagonal order of the table.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
k-SortGiven an array and k, decide whether the array can be sorted when only elements with equal remainders mod k may be swapped.	Easy3	SortingImplementation	No attempts yet	2s	1024 MB	Judgeable
Traffic Light BulbsGiven the light phase lengths and a day length T, compute the total seconds the red, yellow, and green bulbs are each lit during the day.	Easy3	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
TravelatorGiven the airport points and two speeds, find the minimum time for Bob to reach terminal A, either walking directly or riding the travelator to its end.	Easy3	GeometryMath	No attempts yet	2s	1024 MB	Judgeable
TriangleCount the right triangles with integer sides (unordered) whose area is exactly S, where S is at most 10,000.	Easy3	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Traffic JamGiven cars with start delays a_i and a repeating green-red light, find the time the last car passes the light.	Easy3	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
ElectionsCount the ballots numbered 1 to n that are not divisible by any of the k chosen numbers.	Easy3	ArrayImplementation	No attempts yet	2s	1024 MB	Judgeable
BlocksGiven n distinct numbers in a row, find every split point k where the first k numbers are all smaller than the rest, and list those k values.	Easy3	ArrayImplementation	No attempts yet	2s	1024 MB	Judgeable
HaircutAssign each of n residents to one of k barbers so that client counts differ by at most 1, and no barber cuts their own hair.	Easy3	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
SatelliteGiven n timed runs for each of k implementations, compute how many cross-implementation run pairs each one wins by being strictly faster.	Easy3	SortingPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
PhotographCount the calendar days that match a DD.MM.YYYY pattern with hidden digits marked by ? and fall between two given dates.	Easy3	ImplementationBrute force	No attempts yet	2s	1024 MB	Judgeable
CipherGiven a lowercase string of at most 1000 characters, print its lexicographically largest substring.	Easy3	String	No attempts yet	2s	1024 MB	Judgeable
MessageGiven k, find the k-th smallest prime p such that 2p + 1 is also prime.	Easy3	Number theoryImplementation	No attempts yet	2s	1024 MB	Judgeable
Semi-Case-Insensitive SearchGiven item names and queries, report for each query whether it matches an item, ignoring letter case only when that item is always written the same way in the list.	Easy3	Hash mapString	No attempts yet	2s	1024 MB	Judgeable
Cut!Split an n by m grid into connected pieces of exactly k cells each, printing each cell's piece number, or -1 if impossible.	Easy3	ImplementationMatrix+1	No attempts yet	2s	1024 MB	Judgeable
Deoxyribonucleic AcidGiven one DNA chain s and a gene t, determine whether t appears in s or in its complementary chain read in the opposite direction.	Easy3	StringString matching	No attempts yet	2s	1024 MB	Judgeable
Wars of PlanetsSimulate a two-player planet war with ship production, delayed ship movement, and battles, then answer each planet's owner and ship count.	Easy3	SimulationImplementation+1	No attempts yet	2s	1024 MB	Judgeable
A Simple ProblemGiven the colors of the four triangles on each of three squares, decide whether the squares can be joined edge to edge in a row with matching colors, with rotations allowed.	Easy3	Brute forceImplementation	No attempts yet	2s	1024 MB	Judgeable
Big Square PieceGiven an n by m cake and k cuts parallel to its sides, find the side of the largest square that fits in one resulting piece.	Easy3	SortingImplementation	No attempts yet	2s	1024 MB	Judgeable
Sneaky Parking AttendantGiven an n by m grid of unit cells, find the fewest pillars that each touch or sit inside every cell.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
ConfessionGiven a string, change the case of the fewest letters so that the letters alternate in case, skipping non-letter characters.	Easy3	StringImplementation	No attempts yet	2s	1024 MB	Judgeable
Dragon TeethGiven two rows of tooth lengths and a limit d, find the smallest shift of the lower row so every facing pair sums to at most d.	Easy3	ArrayBrute force	No attempts yet	2s	1024 MB	Judgeable
Potion of the Power of NumbersCount the integers up to n of the form 2^a * 3^b, where a is at least 1 and b is at least 0.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
ToursGiven n daily city visits, find the start day of the k-day window that contains the most distinct cities.	Easy3	Sliding windowHash map+1	No attempts yet	2s	1024 MB	Judgeable