Problems

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Total results29,413 problems

Fried rice for me
Medium6
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Enemy of My Enemy
Medium6
Union-find, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Chocolate Chip Cake
Medium6
Array, Simulation+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Am I Fired?
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Matryoshka
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sum of a Geometric Series
Medium6
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tetris Remastered
Medium6
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Nice Shape
Medium6
Hash map, Implementation+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Snowman
Medium6
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Teacher Sorting
Medium6
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Paired Up
Medium6
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lonely Photo
Medium6
String, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Walking Home
Medium6
Dynamic programming, Matrix+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Algorithm Class - Selection Sort 3
Medium6
Simulation, Sorting+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Arithmetic Sequence and Queries
Medium6
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rolling Stones
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Snail Top
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Tire Tug
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Plates
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Workout
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Algorithm Class - Selection Sort 6
Medium6
Sorting, Implementation+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Wandering Robot
Medium6
Dynamic programming, Probability+2
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Stable Wall
Medium6
Graph, Topological sort+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Perfect Subarray
Medium6
Prefix sum, Hash map+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Candies
Medium6
Segment tree, Prefix sum+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Boring Numbers
Medium6
Dynamic programming, Math+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Rugby
Medium6
Sorting, Greedy+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Parcels
Medium6
Matrix, Math+1
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Contention
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Circuit Board
Medium6
Sliding window, Two pointers+1
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
X or What?
Medium6
Prefix sum, Bit manipulation+1
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Food Stalls
Medium6
Heap, Sorting+1
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable
Cherries Mesh
Medium6
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Street Checkers
Medium6
Number theory, Math+2
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Teach Me
Medium6
Bit manipulation, Combinatorics+2
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Book Reading
Medium6
Math, Number theory+2
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Lucky Dip
Medium6
Dynamic programming, Probability+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Sherlock and the Bit Strings
Medium6
Prefix sum, Dynamic programming
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
The Devil's Offer
Medium6
Math, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
String Splitting
Medium6
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Palindromic Sequence
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Product Triplets
Medium6
Array, Hash map+2
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Math Encoder
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Christmas Tree
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Magical Thinking v2
Medium6
Math, Brute force
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Copy & Paste
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Ticket Trouble
Medium6
Graph, Greedy+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Burger Optimization
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
CEO Search
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Centrists
Medium6
String, Sorting+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Baby Hongyoon
Medium6
Bit manipulation, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Train Trip
Medium6
Shortest path, Array+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Inconstant Ordering
Medium6
Greedy, String+2
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Irrefutable Outcome
Medium6
Game theory, Dynamic programming+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Garden (Hard)
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Insertion Sort 4
Medium6
Sorting, Implementation+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Algorithm Class - Insertion Sort 6
Medium6
Array, Hash map+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Algorithm Class - Merge Sort 1
Medium6
Divide and conquer, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Merge Sort 2
Medium6
Sorting, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Merge Sort 3
Medium6
Simulation, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Guessing
Medium6
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Present
Medium6
Math, Geometry+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
KPart
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Algorithm Class - Quick Sort 3
Medium6
Sorting, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Banner
Medium6
Brute force, Combinatorics+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Shiritori
Medium6
Graph, DFS
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
International Olympiad in Informatics (IOI)
Medium6
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stairs
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Addition (a+b problem)
Medium6
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
DNA Synthesizer
Medium6
String matching, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Contest
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ski
Medium6
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Logo Mark
Medium6
Implementation, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Sheet
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Flu
Medium6
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Origami
Medium6
Sorting, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Factorial (Factorial)
Medium6
Number theory, Math+2
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Elephant Handler (Route)
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Algorithm Class - Heap Sort 1
Medium6
Simulation, Heap+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cookie Game
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Light Show
Medium6
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Meeting
Medium6
Sorting, Intervals+2
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Interpretation
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Broken Tree
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Doomsday
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Sum and product
Medium6
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cutting
Medium6
Geometry, Binary search+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Landmark Construction
Medium6
Math, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Field
Medium6
Binary search, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hacking
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rectangles
Medium6
Hash map, Geometry+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Largest remainder
Medium6
Sorting, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
АВТОБУСИ
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Alpha
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
150 MB
Judgeable
Brackets
Medium6
Prefix sum, Stack+2
No attempts yet
Time limit
0.3s
Memory limit
1024 MB
Judgeable
ПУКАНКИ
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
0.2s
Memory limit
1024 MB
Judgeable
Gahee and the Buildings
Medium6
Array, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Snowboard
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
School Concert
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Number of zeros
Medium6
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Fried rice for meGiven D, N, M, and K, find the most fried rice orders possible while the total dumplings received stay at the maximum.	Medium6	MathImplementation	No attempts yet	1s	512 MB	Judgeable
Enemy of My EnemyGiven friend and enemy relations between people, derive implied relations using the enemy-of-my-enemy rule, then answer queries with Friend, Enemy, Unknown, or Error.	Medium6	Union-findGraph+2	No attempts yet	1s	512 MB	Judgeable
Chocolate Chip CakeAfter each operation that adds a chip to a full row or column of an n by n cake, report how many cells hold the maximum number of chips.	Medium6	ArraySimulation+2	No attempts yet	0.5s	512 MB	Judgeable
Am I Fired?Choose one of four activities each day for N days to maximize satisfaction, subject to at most A rest days, no two lounges in a row, and at least B reading or small-room days.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	512 MB	Judgeable
MatryoshkaPartition N dolls into groups, each group being a consecutive range of distinct sizes, and maximize the sum over groups of (largest size) times (group size).	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	1024 MB	Judgeable
Sum of a Geometric SeriesGiven N up to 10^12, find a geometric series with at least 3 positive integer terms and integer ratio above 1 whose sum is N, or report that none exists.	Medium6	MathNumber theory+2	No attempts yet	2s	1024 MB	Judgeable
Tetris RemasteredGiven column heights with no gaps underneath, drop 1-by-x horizontal pieces to finish a full n-wide rectangle using the fewest pieces.	Medium6	GreedyArray+2	No attempts yet	1s	512 MB	Judgeable
Nice ShapeGiven n rooks on a board, find the fewest single-row or single-column moves that leave four rooks at the corners of a rectangle.	Medium6	Hash mapImplementation+1	No attempts yet	4s	512 MB	Judgeable
SnowmanGiven a string of section classes and a length k, find the lexicographically smallest length-k string you can form by walking on the string with possible repeats.	Medium6	GreedyString+2	No attempts yet	1s	512 MB	Judgeable
Teacher SortingGiven an array, decide whether it can be sorted by disjoint swaps (each index used at most once) and output such a swap sequence.	Medium6	SortingGreedy+2	No attempts yet	1s	512 MB	Judgeable
Paired UpGiven N cows on a number line with weights, form a maximal set of pairs within distance K and find the minimum (T=1) or maximum (T=2) total weight of unpaired cows.	Medium6	Dynamic programmingArray	No attempts yet	2s	1024 MB	Judgeable
Lonely PhotoCount substrings of length at least three that contain exactly one G or exactly one H in a binary string of up to 5*10^5 characters.	Medium6	StringCombinatorics+2	No attempts yet	2s	1024 MB	Judgeable
Walking HomeCount monotone grid paths from top-left to bottom-right that avoid haybales and change direction at most K times, with K at most 3.	Medium6	Dynamic programmingMatrix+2	No attempts yet	2s	1024 MB	Judgeable
Algorithm Class - Selection Sort 3Given a permutation of N distinct values, report the pair of values exchanged at the K-th swap of selection sort, or -1 if fewer than K swaps occur.	Medium6	SimulationSorting+2	No attempts yet	3s	512 MB	Judgeable
Arithmetic Sequence and QueriesGiven an arithmetic sequence with first term a and difference d, answer queries for the sum or the gcd of a contiguous range of terms.	Medium6	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Rolling StonesGiven N villages with sand castle counts and K stone start positions, choose M wall villages to maximize the castles that stones cannot destroy, breaking ties lexicographically.	Medium6	Dynamic programmingGreedy	No attempts yet	1s	512 MB	Judgeable
Snail TopFor a half-disc of radius R (x^2+y^2 <= R^2, x >= 0), find the integer point strictly inside it that maximizes the area swept when the half-disc rotates one full turn about that axis.	Medium6	GeometryMath+2	No attempts yet	1s	512 MB	Judgeable
Tire TugDistribute M students across N tires, beating the opponent's count on chosen tires to maximize the score gap and report whether a win, draw, or loss is the best outcome.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	1024 MB	Judgeable
PlatesChoose exactly P plates from N stacks of K plates, where taking a plate requires taking every plate above it, to maximize total beauty.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	20s	1024 MB	Judgeable
WorkoutGiven a strictly increasing sequence and up to K inserted integers, minimize the largest gap between consecutive sessions.	Medium6	Binary searchGreedy+2	No attempts yet	20s	1024 MB	Judgeable
Algorithm Class - Selection Sort 6Given distinct arrays A and B, decide whether A equals B at some moment during selection sort, including before any swap.	Medium6	SortingImplementation+2	No attempts yet	3s	512 MB	Judgeable
Wandering RobotA robot moves right or down at random on a W by H grid with a rectangular hole removed; find the probability it reaches the bottom-right corner without entering the hole.	Medium6	Dynamic programmingProbability+2	No attempts yet	15s	1024 MB	Judgeable
Stable WallGiven a rectangular grid of letters where each letter is one polyomino, find an order in which the polyominoes can be placed so every piece is always supported from below, or report that no such order exists.	Medium6	GraphTopological sort+2	No attempts yet	20s	1024 MB	Judgeable
Perfect SubarrayCount the contiguous non-empty subarrays whose total sum is a perfect square, with array values between -100 and 100.	Medium6	Prefix sumHash map+2	No attempts yet	Not set	1024 MB	Judgeable
CandiesMaintain an array under point updates and answer range queries for the alternating weighted sum sum of (-1)^(i-l) * Ai * (i-l+1).	Medium6	Segment treePrefix sum+1	No attempts yet	20s	1024 MB	Judgeable
Boring NumbersCount numbers in [L, R] whose digits alternate odd, even, odd, even by position, using a digit-DP style prefix count.	Medium6	Dynamic programmingMath+2	No attempts yet	20s	1024 MB	Judgeable
RugbyGiven N grid points, find the minimum total Manhattan distance to move them onto N consecutive points of one horizontal line, choosing the line and the assignment.	Medium6	SortingGreedy+2	No attempts yet	Not set	1024 MB	Judgeable
ParcelsGiven a grid of delivery offices, find the one extra office placement that minimizes the largest Manhattan distance from any square to its nearest office.	Medium6	MatrixMath+1	No attempts yet	15s	1024 MB	Judgeable
ContentionGiven Q seat bookings on a row of N seats, find the largest k such that some entry order gives every booking at least k seats.	Medium6	Binary searchGreedy+1	No attempts yet	15s	1024 MB	Judgeable
Circuit BoardFind the largest axis-aligned subrectangle where each row's max minus min is at most K, and report its number of squares.	Medium6	Sliding windowTwo pointers+1	No attempts yet	15s	1024 MB	Judgeable
X or What?After each point update, find the length of the longest subinterval whose xor-sum has an even number of set bits.	Medium6	Prefix sumBit manipulation+1	No attempts yet	40s	1024 MB	Judgeable
Food StallsPick one warehouse spot and K stall spots from N candidates to minimize total cost, where each stall also pays its distance to the warehouse.	Medium6	HeapSorting+1	No attempts yet	30s	1024 MB	Judgeable
Cherries MeshEach pair of cherries is joined by a red strand of weight 2 or, if listed, a black strand of weight 1. Keep a spanning tree of minimum total weight.	Medium6	Minimum spanning treeUnion-find+2	No attempts yet	15s	1024 MB	Judgeable
Street CheckersCount numbers X in [L, R] where the counts of odd and even divisors of X differ by at most 2, with R-L up to 100000 and up to 100 test cases.	Medium6	Number theoryMath+2	No attempts yet	40s	1024 MB	Judgeable
Teach MeEach employee knows up to 5 skills. Count ordered pairs (i, j) where employee i knows some skill that employee j does not.	Medium6	Bit manipulationCombinatorics+2	No attempts yet	40s	1024 MB	Judgeable
Book ReadingFor each reader, count the pages whose number is a multiple of the reader's R and not among the M torn pages, then sum those counts over all readers.	Medium6	MathNumber theory+2	No attempts yet	40s	1024 MB	Judgeable
Lucky DipWith N items in a bag and up to K redips, compute the expected value of the final item under the optimal stopping rule.	Medium6	Dynamic programmingProbability+2	No attempts yet	Not set	1024 MB	Judgeable
Sherlock and the Bit StringsGiven N and K interval constraints on the count of 1s, output the P-th lexicographically smallest bit string that satisfies all of them.	Medium6	Prefix sumDynamic programming	No attempts yet	20s	1024 MB	Judgeable
The Devil's OfferGiven K and N, find the smallest integer X such that after paying K and multiplying the rest by N, the result is at least X, or report -1 if no such X exists.	Medium6	MathBinary search+2	No attempts yet	1s	512 MB	Judgeable
String SplittingCount the ways to cut a digit string into K nonempty contiguous pieces so that no piece starts with a 0 (the piece "0" alone is allowed).	Medium6	Dynamic programmingString+2	No attempts yet	1s	512 MB	Judgeable
Palindromic SequenceGiven L letters, a length limit N, and K, find the length of the Kth smallest palindrome in lexicographic order, or 0 if none exists.	Medium6	CombinatoricsMath+1	No attempts yet	20s	1024 MB	Judgeable
Product TripletsCount index triplets where one value equals the product of the other two, handling zeros and duplicate values.	Medium6	ArrayHash map+2	No attempts yet	40s	1024 MB	Judgeable
Math EncoderGiven a sorted list, sum the difference between the largest and smallest element over all non-empty subsets, modulo 1000000007.	Medium6	CombinatoricsMath+2	No attempts yet	20s	1024 MB	Judgeable
Christmas TreeGiven a grid of green and white cells, find the most green cells in a stack of K good triangles, where each triangle's top sits in the row below the previous base.	Medium6	Dynamic programmingMatrix+1	No attempts yet	Not set	1024 MB	Judgeable
Magical Thinking v2Given friends' true-false answer lists and their scores, find the highest score you could have gotten under some answer key consistent with all of them.	Medium6	MathBrute force	No attempts yet	20s	1024 MB	Judgeable
Copy & PasteGiven a target string, find the fewest type, copy, and paste operations needed to build it exactly with no extra letters.	Medium6	Dynamic programmingString+1	No attempts yet	40s	1024 MB	Judgeable
Ticket TroubleEach printed ticket (a, b) with a <= b can be assigned to seat (a, b) or (b, a); find the maximum number of tickets assignable to a single row.	Medium6	GraphGreedy+2	No attempts yet	20s	1024 MB	Judgeable
Burger OptimizationPlace K ingredients with given ideal distances into a symmetric stack to minimize the sum of squared deviations from their actual distance-to-bun values.	Medium6	GreedySorting+2	No attempts yet	20s	1024 MB	Judgeable
CEO SearchGiven counts of employees at distinct experience levels, find the smallest experience level for a new CEO so that every employee can be assigned a higher-level direct manager within capacity limits.	Medium6	GreedySorting+2	No attempts yet	20s	1024 MB	Judgeable
CentristsGiven three distinct equal-length strings, decide for each whether some alphabet ordering makes that string the median when the three are sorted lexicographically.	Medium6	StringSorting+2	No attempts yet	20s	1024 MB	Judgeable
Baby HongyoonFind a contiguous subarray whose bitwise OR equals K, or report that none exists.	Medium6	Bit manipulationTwo pointers+2	No attempts yet	1s	1024 MB	Judgeable
Train TripGiven N cities, each with a train covering an interval [L_i, R_i] that contains city i, find the fewest train rides from U to V, or -1 if impossible.	Medium6	Shortest pathArray+1	No attempts yet	4s	1024 MB	Judgeable
Inconstant OrderingGiven block sizes, build the alphabetically smallest string starting with A where letters strictly increase in odd blocks and strictly decrease in even blocks.	Medium6	GreedyString+2	No attempts yet	10s	1024 MB	Judgeable
Irrefutable OutcomePlayers alternately remove end pieces of their own color from an I/O row; output the winner and the winner's optimal score.	Medium6	Game theoryDynamic programming+1	No attempts yet	20s	1024 MB	Judgeable
Garden (Hard)Fill an N by M grid where each cell equals the XOR of its left and top neighbors, and report the value at row N, column M given the left and top edge colors.	Medium6	CombinatoricsMath+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Insertion Sort 4Given N distinct integers, run the given insertion sort and report the value written into the array at the K-th save operation, or -1 if fewer than K saves occur.	Medium6	SortingImplementation+2	No attempts yet	3s	512 MB	Judgeable
Algorithm Class - Insertion Sort 6Given arrays A and B, decide whether the array A ever equals B at any moment while insertion sort sorts A in ascending order.	Medium6	ArrayHash map+1	No attempts yet	3s	512 MB	Judgeable
Algorithm Class - Merge Sort 1Simulate the given merge sort and report the value written into the array at the K-th store operation, or -1 if fewer than K stores occur.	Medium6	Divide and conquerSorting+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Merge Sort 2Simulate merge sort on N distinct integers and print the whole array right after the K-th assignment into A, or -1 if fewer than K assignments happen.	Medium6	SortingDivide and conquer+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Merge Sort 3Given two arrays A and B of distinct integers, the task is to print 1 if A ever equals B while merge sort sorts A, otherwise print 0.	Medium6	SimulationDivide and conquer+1	No attempts yet	1s	512 MB	Judgeable
GuessingGiven modular sum equations between hidden card values, find the minimum flip cost that determines all values and output one consistent assignment.	Medium6	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
PresentCount the squares whose four vertices are pillars of an n by n grid and whose area is at least a.	Medium6	MathGeometry+2	No attempts yet	0.5s	512 MB	Judgeable
KPartFor each array, count and list the values of K such that every contiguous window of length K can be split into two parts with equal sums.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Algorithm Class - Quick Sort 3Simulate the given quicksort (Lomuto partition, last element as pivot) on array A and report whether any intermediate state equals array B.	Medium6	SortingDivide and conquer+2	No attempts yet	1s	512 MB	Judgeable
BannerCount the axis-parallel rectangles of four pillars in an H by W grid whose corners include black, gray, and white pillars.	Medium6	Brute forceCombinatorics+1	No attempts yet	1.5s	1024 MB	Judgeable
ShiritoriOrder all N ten-digit words so each word begins with the last two-digit character of the previous word, choosing the dictionary-smallest valid sequence.	Medium6	GraphDFS	No attempts yet	5s	1024 MB	Judgeable
International Olympiad in Informatics (IOI)Given each contestant's partial total, decide who is guaranteed a gold medal and who still has a chance, using the rule that gold goes to the top 1/12 of contestants by final total.	Medium6	SortingGreedy+2	No attempts yet	1s	1024 MB	Judgeable
StairsCount the increasing sequences of steps from 1 to N whose total height difference is at most P, modulo 1234567.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	1.5s	1024 MB	Judgeable
Addition (a+b problem)Add two huge integers given in run-length encoded decimal form and print the sum in the same run-length encoded format.	Medium6	ImplementationMath+2	No attempts yet	1s	1024 MB	Judgeable
DNA SynthesizerFind the fewest small DNA strands that, joined with at least one shared character at each overlap, produce the target strand.	Medium6	String matchingDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
ContestGiven 2N athlete scores, some with unknown countries, assign the unknown scores so that country C gets the best possible rank.	Medium6	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
SkiGiven a DAG of ski paths with distances and speeds, find the route from any lift-reachable point to Hotel IOI minimizing the total time divided by total distance.	Medium6	GraphDynamic programming+2	No attempts yet	1s	1024 MB	Judgeable
Logo MarkColor the used cells of a W by H grid with exactly K red cells and the rest white, so that both the red and white regions are line-symmetric.	Medium6	ImplementationGreedy+1	No attempts yet	3s	1024 MB	Judgeable
SheetGiven a top-down color photo of N stacked rectangular sheets on a table, find any order in which the sheets could have been placed.	Medium6	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
FluAn outbreak starts at city 1 and each day spreads to cities within distance d; count how many cities have an active outbreak exactly k days later, where each outbreak lasts m days and every city has at most 10 neighbors.	Medium6	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
OrigamiGiven up to 5000 axis-aligned rectangles, each at most 20 by 20, on a huge grid, find the maximum overlap count and the total area covered by exactly that many rectangles.	Medium6	SortingPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Factorial (Factorial)Given n up to 1e8, find the smallest m such that m! is divisible by n.	Medium6	Number theoryMath+2	No attempts yet	0.5s	1024 MB	Judgeable
Elephant Handler (Route)Find the cheapest path from booth 1 to booth 2 in a geometric graph where each turn at a booth must not form an acute angle with the incoming road.	Medium6	GraphShortest path+2	No attempts yet	1s	1024 MB	Judgeable
Algorithm Class - Heap Sort 1Simulate min-heap sort on a given array and report the two values exchanged at the K-th swap, or -1 if fewer than K swaps occur.	Medium6	SimulationHeap+2	No attempts yet	1s	512 MB	Judgeable
Cookie GameGiven a tree where each vertex has 1 or 2 cookies, find the maximum number of cookies a piece can eat when it starts anywhere and moves along edges.	Medium6	TreeDynamic programming+1	No attempts yet	8s	1024 MB	Judgeable
Light ShowGiven the colors of lamps on all four sides of an R by C grid, count the cells that receive at least one lamp of each of the three colors.	Medium6	ImplementationMath+2	No attempts yet	1s	1024 MB	Judgeable
MeetingEach member gives intervals during which they can attend if the meeting starts inside; find the start time covered by the most members' intervals.	Medium6	SortingIntervals+2	No attempts yet	6s	1024 MB	Judgeable
InterpretationGiven a string of 0s and 1s of length up to 300, count the valid bracket strings that encode to it, where each matched pair is written as 01 or 10.	Medium6	Dynamic programmingString	No attempts yet	1s	512 MB	Judgeable
Broken TreeGiven a tree whose edges are oriented, flip as few edges as possible so that some vertex can reach every other vertex.	Medium6	TreeDFS+2	No attempts yet	1s	512 MB	Judgeable
DoomsdayGiven a weighted undirected graph, a base at 0, and sets of water and food depots, find the minimum time to visit one depot of each type and return to base.	Medium6	GraphShortest path+2	No attempts yet	5s	1024 MB	Judgeable
Sum and productGiven n, count the non-increasing sequences of n positive integers whose product equals their sum.	Medium6	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
CuttingEach request cuts a V-shaped wedge upward from a lattice point, and the task is to print the remaining area after every cut.	Medium6	GeometryBinary search+1	No attempts yet	0.5s	1024 MB	Judgeable
Landmark ConstructionGiven three pairwise distances a, b, c, place three intersections on a grid of 8 x 10^8 roads per direction that realize them, or print -1.	Medium6	MathGeometry+1	No attempts yet	1s	1024 MB	Judgeable
FieldFind the smallest M so that every M by M square placed inside the N by N grid has sum at least K, or report -1.	Medium6	Binary searchPrefix sum+2	No attempts yet	2s	1024 MB	Judgeable
HackingGiven preliminary scores and Ivaylo's rank, find the minimum number of other participants' solutions he must hack to gain 100 each and finish first alone.	Medium6	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
RectanglesCount how many distinct rectangles have all four vertices among N given lattice points.	Medium6	Hash mapGeometry+2	No attempts yet	2s	1024 MB	Judgeable
Largest remainderGiven N huge positive integers (up to 50 digits), find the maximum value of a_i mod a_j over all ordered pairs i, j. The sequence has at least two distinct values.	Medium6	SortingMath+2	No attempts yet	1s	1024 MB	Judgeable
АВТОБУСИCount multiples of lcm(a,b,c) that fall inside day d's time window [dt, dt + t - 1], given three bus periods a, b, c.	Medium6	MathNumber theory+2	No attempts yet	1s	1024 MB	Judgeable
AlphaGiven 26 names, count the ways to pick one letter from each name in order so that all 26 alphabet letters appear exactly once.	Medium6	Dynamic programmingBit manipulation	No attempts yet	2s	150 MB	Judgeable
BracketsGiven a fixed parenthesis string, answer T queries asking whether the substring from position L to R is a balanced bracket sequence.	Medium6	Prefix sumStack+2	No attempts yet	0.3s	1024 MB	Judgeable
ПУКАНКИSplit the line of N popcorn bags into K consecutive nonempty groups; find the minimum possible maximum group sum divided by eating speed S, rounded up.	Medium6	Binary searchGreedy+2	No attempts yet	0.2s	1024 MB	Judgeable
Gahee and the BuildingsGiven N buildings and counts a (visible from the left) and b (visible from the right), output the lexicographically smallest height sequence, or -1 if none exists.	Medium6	ArrayGreedy+1	No attempts yet	1s	512 MB	Judgeable
SnowboardCount paths from the top row to the bottom row of an N by M grid, moving down or diagonally down, that pass through exactly P cells, modulo 262.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
School ConcertGiven K burners with different speeds and N discs to burn, find the minimum time to finish all discs when each burner works continuously.	Medium6	Binary searchGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Number of zerosGiven N and K, compute the binomial coefficient C(N,K) and count how many zero digits appear in its decimal representation.	Medium6	MathCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable