Problems

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Total results29,458 problems

Bookshelf
Medium4
Math, Geometry
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Without Nines
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Thanos's Arrival
Medium4
Backtracking, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Armor Hall
Medium4
Prefix sum, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Restaurant
Medium4
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Polynomials
Medium4
String, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Max's Power Tower
Medium4
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ventilation
Medium4
Tree, DFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Digital Riddle
Medium4
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Escalator
Medium4
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Who wants to be a millionaire?
Medium4
Greedy, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tanya, the Balls, and XOR
Medium4
Math, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pursuit
Medium4
Brute force, Backtracking+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sparkling Pluses
Medium4
Matrix, Dynamic programming
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Castle for Adam
Medium4
Math, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Redistributing Stones
Medium4
Sorting, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Logan and Queries
Medium4
Prefix sum, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Best Gift Is an Array!
Medium4
Sliding window, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Transistor Repair
Medium4
Number theory, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Way Home
Medium4
Stack, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Anagrams 2
Medium4
Array, Hash map+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Cramped but Not Offended
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crossings of Crossings
Medium4
BFS, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Colors
Medium4
Math, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Well-Fed Game
Medium4
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Droids and the Hangar
Medium4
Prefix sum, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Candies
Medium4
Sliding window, Hash map
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sly Fox
Medium4
Array, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Minimum Range Subset
Medium4
Sorting, Sliding window
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Capital
Medium4
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sequence
Medium4
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gureum's Job Prep Minimum Time
Medium4
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Walk in the Park
Medium4
Sorting, Prefix sum+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Mutant Ants
Medium4
Stack, Two pointers
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Splitting Into Cells
Medium4
Math, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bank Queue
Medium4
Array, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Relatives
Medium4
Bit manipulation, Hash map
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Vampire Basketball
Medium4
Sorting, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Rods
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Map
Medium4
String, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Miss Me?
Medium4
String, Two pointers
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Unlocking
Medium4
Dynamic programming, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
T-X vs T-850
Medium4
Geometry, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Berries for the Lemurs
Medium4
Prefix sum, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Let's fly!
Medium4
Sorting, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Appointments
Medium4
String, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hospital
Medium4
Tree, DFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Easy Word
Medium4
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cars in Byteland
Medium4
Queue, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Championship
Medium4
Sorting, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Where Are My Dragons?
Medium4
Simulation, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Saruman
Medium4
Prefix sum, Binary search
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Elven Pyramid
Medium4
Array, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sewer
Medium4
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Catching the Hulk
Medium4
Geometry, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Typewriter
Medium4
String, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Curse of the Black Pearl
Medium4
String, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Harry Potter and the Sorting Hat
Medium4
Bit manipulation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Moose Calf
Medium4
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fence Painting
Medium4
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lambda
Medium4
Tree, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sums of Blue and Red Cubes
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Clock
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tail of a Graph
Medium4
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Paper Cups
Medium4
Heap, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shortening Links
Medium4
String, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
XOR
Medium4
Trie, Bit manipulation
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
ЕГЭ
Medium4
Bit manipulation, Math
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Triangular Key
Medium4
Implementation, Matrix
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Keep the ranks - 2
Medium4
Greedy, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hold the line - 3
Medium4
Prefix sum, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gagarin Cup
Medium4
Probability, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Backup System
Medium4
Simulation, Stack+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Martian Friend
Medium4
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Journey
Medium4
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Electronic Clock
Medium4
Implementation, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Super Massive Black Hole
Medium4
Sorting, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Playlist
Medium4
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Roads
Medium4
Shortest path, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Card Trick
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crossroad
Medium4
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chemical Cipher
Medium4
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Glue!
Medium4
BFS, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tree
Medium4
Tree, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Vasya
Medium4
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Wipe it!
Medium4
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Brick towers
Medium4
Prefix sum, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cubes
Medium4
String, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Most Global Positioning System
Medium4
Geometry, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Diligent Beavers
Medium4
Graph, BFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Exponentiation
Medium4
Math, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Art Class
Medium4
Union-find, Array
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Principalities
Medium4
DFS, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Football Formation
Medium4
Brute force, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Festive Olympiad
Medium4
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Awards
Medium4
Math, Combinatorics
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Big Horse Race
Medium4
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Advertising Poster
Medium4
Dynamic programming, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Songi in the Strange Hotel
Medium4
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Last-minute cramming
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
BookshelfGiven book height h and span r, find the fewest extra books needed so that toppling the leftmost book knocks over the rightmost one.	Medium4	MathGeometry	No attempts yet	2s	1024 MB	Judgeable
Without NinesCount the integers from l to r that contain no digit 9, where l and r are up to 10^15 and neither contains a 9.	Medium4	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Thanos's ArrivalGiven a valid date as YYYY MM DD, list every valid date that can be formed by rearranging its eight digits, sorted from earliest to latest.	Medium4	BacktrackingImplementation	No attempts yet	2s	1024 MB	Judgeable
Armor HallGiven weighted points on a line, find the integer position that minimizes total weighted distance, taking the smallest coordinate on ties.	Medium4	Prefix sumArray+1	No attempts yet	2s	1024 MB	Judgeable
RestaurantGiven three priority rankings of n restaurants, find the one that at least two of the three diners prefer over every other restaurant, or report -1.	Medium4	ArrayImplementation	No attempts yet	1s	1024 MB	Judgeable
PolynomialsGiven polynomials in n and m as strings, expand each product of factors, combine like terms, and print the simplified polynomials in the required format.	Medium4	StringImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Max's Power TowerGiven a right-associative power tower of n natural numbers, find its value modulo 3.	Medium4	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
VentilationGiven a tree of n nodes, answer each query (s, t) with the neighbor of s on the unique path from s to t.	Medium4	TreeDFS+1	No attempts yet	3s	1024 MB	Judgeable
Digital RiddleGiven n numbers and at most k single-digit replacements, find the largest possible increase in their sum.	Medium4	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
EscalatorCount the total digits written on the labeled steps: step 1, every multiple of ten up to n, and the last step n.	Medium4	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Who wants to be a millionaire?Given n, print the first n prizes: a_1 is 100, and each next prize is the smallest round number at least twice the previous one.	Medium4	GreedyImplementation	No attempts yet	1s	1024 MB	Judgeable
Tanya, the Balls, and XORGiven n, compute the sum of i XOR j over all pairs 1 <= i < j <= n, modulo 10^9+7.	Medium4	MathBit manipulation	No attempts yet	1s	1024 MB	Judgeable
PursuitSplit the digits of x into k numbers without leading zeros so that each adjacent pair differs by between l and r, then count the splits.	Medium4	Brute forceBacktracking+1	No attempts yet	2s	1024 MB	Judgeable
Sparkling PlusesGiven an n by m matrix of 0s and 1s, find the largest plus shape made of 1s and print its size and the row and column of its center.	Medium4	MatrixDynamic programming	No attempts yet	4s	1024 MB	Judgeable
Castle for AdamGiven a log of length l, find the maximum number of pieces with pairwise distinct integer lengths that sum to l.	Medium4	MathGreedy	No attempts yet	2s	1024 MB	Judgeable
Redistributing StonesGiven n stone positions, find the fewest single-stone moves needed so the stones fill n consecutive chests, one per chest.	Medium4	SortingSliding window+1	No attempts yet	2s	1024 MB	Judgeable
Logan and QueriesRearrange an array so that the total of all q range-sum query answers is as large as possible, then report that maximum sum.	Medium4	Prefix sumGreedy+1	No attempts yet	2s	1024 MB	Judgeable
The Best Gift Is an Array!Find a contiguous subarray of a with the same length as p whose elements match p as a multiset, and print its start position or NO.	Medium4	Sliding windowHash map+1	No attempts yet	2s	1024 MB	Judgeable
Transistor RepairGiven n leg resistances, find three of them whose sum is A and product is B, or report -1 if none exist.	Medium4	Number theoryHash map+1	No attempts yet	2s	1024 MB	Judgeable
Way HomeGiven a stream of signs where positive x activates x, -x cancels x, and 0 cancels the active sign, print the active sign after each step.	Medium4	StackImplementation	No attempts yet	2s	1024 MB	Judgeable
Anagrams 2Find the longest contiguous subarray of the first array and one of the second array that are anagrams, and print its length and start indices.	Medium4	ArrayHash map+1	No attempts yet	3s	1024 MB	Judgeable
Cramped but Not OffendedGiven an n by m room and a target p, decide whether two cuts can split the room into three rectangles whose perimeters sum to p.	Medium4	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Crossings of CrossingsFind the fewest crossings needed to walk from house 0 on the left side to house f on the right side, given the crossings on each side and across the avenue.	Medium4	BFSShortest path+1	No attempts yet	2s	1024 MB	Judgeable
ColorsGiven n color numbers, count how many distinct colors can be produced by repeatedly taking the floor midpoint of two obtained colors.	Medium4	MathGreedy	No attempts yet	2s	1024 MB	Judgeable
Well-Fed GameGiven four moduli d_i and remainders r_i, find the smallest nonnegative x that satisfies x ≡ r_i (mod d_i) for all four congruences.	Medium4	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Droids and the HangarGiven a row of rock cells and droids plus a string of L and R moves, find which droids never hit a rock and print their positions.	Medium4	Prefix sumImplementation+1	No attempts yet	2s	1024 MB	Judgeable
CandiesFind the length of the longest contiguous run of candies that contains exactly two distinct types.	Medium4	Sliding windowHash map	No attempts yet	2s	1024 MB	Judgeable
Sly FoxGiven n cards, find the one card whose removal leaves the largest GCD among the rest, and print its index and that GCD.	Medium4	ArrayNumber theory	No attempts yet	2s	1024 MB	Judgeable
Minimum Range SubsetGiven n numbers, choose k of them so that the gap between the largest and smallest chosen values is minimal, and print the subset.	Medium4	SortingSliding window	No attempts yet	2s	1024 MB	Judgeable
CapitalGiven a digit sum a and a digit limit n, find the largest number whose digits sum to a and has at most n digits, or print -1.	Medium4	GreedyMath+1	No attempts yet	2s	1024 MB	Judgeable
SequenceGiven a sequence a, find any sequence b of length n+2 where each a_i equals the sum of three consecutive b values.	Medium4	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
Gureum's Job Prep Minimum TimePick p_j problems at each difficulty so that solving times plus rests are minimized, where each difficulty step costs a fixed 60 minutes of rest.	Medium4	SortingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Walk in the ParkGiven vases with water a_i and drain rates b_i, print the total water left at each integer time from 0 to t.	Medium4	SortingPrefix sum+1	No attempts yet	4s	1024 MB	Judgeable
Mutant AntsAnts move right one unit per second and each falls into the first free trap it reaches; print the trap number for each ant or -1.	Medium4	StackTwo pointers	No attempts yet	2s	1024 MB	Judgeable
Splitting Into CellsSplit n into k positive parts whose XOR is zero, or report -1 when no such split exists.	Medium4	MathBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Bank QueueGiven a queue with joins, front departures, and queries, count the people in good mood (mood at least x) standing in front of a given person.	Medium4	ArrayPrefix sum	No attempts yet	2s	1024 MB	Judgeable
RelativesCount the pairs of animal numbers whose decimal representations share at least one digit.	Medium4	Bit manipulationHash map	No attempts yet	2s	1024 MB	Judgeable
Vampire BasketballSort Edward's teammates by a shot favorability score that drops with the defenders within distance l, and print their jersey numbers.	Medium4	SortingMath+1	No attempts yet	2s	1024 MB	Judgeable
Magic RodsChoose positive integer ignition times at both ends of each rod so that every rod's last point is lit at distance d_i and all rods finish at the same earliest moment.	Medium4	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
MapGiven a lowercase message with spaces removed, count the ways to pick three letters that form a palindrome in order.	Medium4	StringPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Miss Me?Given a string, decide whether swapping exactly two characters (they may be equal) can turn it into a palindrome.	Medium4	StringTwo pointers	No attempts yet	2s	1024 MB	Judgeable
UnlockingGiven an n by m grid of integers, find the longest path of adjacent cells whose values increase by exactly 1 at each step.	Medium4	Dynamic programmingSorting+1	No attempts yet	2s	1024 MB	Judgeable
T-X vs T-850For each query, decide whether the segment between two points avoids the boundary of a circle, so the shooter can see the target.	Medium4	GeometryMath	No attempts yet	2s	1024 MB	Judgeable
Berries for the LemursGiven n lemurs with love levels a_i, find the sum over each i of a_i times the number of earlier lemurs j whose reach j+a_j extends past i.	Medium4	Prefix sumArray	No attempts yet	2s	1024 MB	Judgeable
Let's fly!Given altitudes h_i and weights a_i, find the single altitude minimizing the sum of \|h_i - x\| * a_i and print that altitude with the minimum cost.	Medium4	SortingPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
AppointmentsGiven a string, delete every occurrence of one character so that the remaining string is lexicographically smallest, and print it.	Medium4	StringGreedy	No attempts yet	2s	1024 MB	Judgeable
HospitalFind a vertex of a weighted tree whose removal leaves components with the smallest possible maximum total population.	Medium4	TreeDFS	No attempts yet	2s	1024 MB	Judgeable
Easy WordGiven a word, find the minimal complexity among its distinct cyclic shifts and how many shifts reach that minimum.	Medium4	StringString matching+1	No attempts yet	2s	1024 MB	Judgeable
Cars in BytelandModels enter and leave a production queue, and for each query the task asks how many models are priced exactly at the current mean price.	Medium4	QueueHash map+1	No attempts yet	2s	1024 MB	Judgeable
ChampionshipGiven N team names, output the team numbers in the table order that makes the concatenated name string lexicographically smallest.	Medium4	SortingString	No attempts yet	2s	1024 MB	Judgeable
Where Are My Dragons?Given a circular corridor where each door leads to a room, find the total minutes to visit all rooms and print the visiting order.	Medium4	SimulationArray+1	No attempts yet	2s	1024 MB	Judgeable
SarumanGiven a non-decreasing array, for each query (length l, sum s) find the start of a contiguous block of l regiments whose total equals s, or report -1.	Medium4	Prefix sumBinary search	No attempts yet	2s	1024 MB	Judgeable
Elven PyramidGiven stacked rings with inner and outer radii, list the rings that must come off before the bottom ring can be removed.	Medium4	ArrayGreedy	No attempts yet	2s	1024 MB	Judgeable
SewerGiven a tree of n manholes and m queries, report the first manhole on the path from l to r for each query.	Medium4	TreeDFS+1	No attempts yet	2s	1024 MB	Judgeable
Catching the HulkGiven a box with a smaller box inside it in 1 to 3 dimensions, find the fewest cuts that leave only the inner box.	Medium4	GeometryImplementation	No attempts yet	2s	1024 MB	Judgeable
TypewriterGiven n words, one per line, find the fewest button presses to type them, where the copy key can reuse the previous line's word.	Medium4	StringGreedy+1	No attempts yet	2s	1024 MB	Judgeable
The Curse of the Black PearlCount the substrings of a string with '?' gaps that can be filled so every character is the same letter.	Medium4	StringTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
Harry Potter and the Sorting HatGiven n and p, find the house of the n-th student, where the house is the number of 1 bits in n-1 taken modulo p.	Medium4	Bit manipulationMath	No attempts yet	2s	1024 MB	Judgeable
Moose CalfFind the path through all N rows whose largest gap between neighboring trees is as small as possible, or report -1 if no path exists.	Medium4	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
Fence PaintingPick one target color for the fence so that repainting every run of non-target boards, at most s per day, takes the fewest days.	Medium4	ArrayImplementation	No attempts yet	2s	1024 MB	Judgeable
LambdaGiven pairs of tubers in a tree whose edges follow a fixed numbering rule, find the smallest tuber number on the path between each pair.	Medium4	TreeImplementation	No attempts yet	1s	1024 MB	Judgeable
Sums of Blue and Red CubesCount the pairs (x, y) with x and y each taken from the integers a to b whose sum lies between c and d inclusive.	Medium4	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
ClockGiven a start and end time on a 12-hour dial, count how many times the minute hand overtakes the hour hand in that interval, endpoints included.	Medium4	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Tail of a GraphGiven a connected undirected graph, find the number of vertices in the longest tail, a path whose inner vertices have no neighbors outside the path.	Medium4	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
Paper CupsGiven n cups with leftover drink amounts, nonempty cups start new stacks and empty cups join the smallest stack; print the largest stack height.	Medium4	HeapGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Shortening LinksGiven a length limit l and a message, shorten each http:// link from left to right into a prefix plus "..." until the message fits, then report any overflow.	Medium4	StringSimulation+1	No attempts yet	2s	1024 MB	Judgeable
XORFor each b_j, find the a_k from the given set that maximizes a_k XOR b_j, with up to 100,000 values in each list.	Medium4	TrieBit manipulation	No attempts yet	4s	1024 MB	Judgeable
ЕГЭGiven k and i, print the seven characters of the k-th string S_k starting at position i, where the strings follow the Thue-Morse doubling rule.	Medium4	Bit manipulationMath	No attempts yet	4s	1024 MB	Judgeable
Triangular KeyRotate a triangular grid of digits 90 degrees in the given direction and print the result in the same triangular format.	Medium4	ImplementationMatrix	No attempts yet	2s	1024 MB	Judgeable
Keep the ranks - 2Given n and k, print a permutation of 1 to n that has exactly k inversions, where an inversion is a pair with the larger value placed first.	Medium4	GreedyArray+1	No attempts yet	2s	1024 MB	Judgeable
Hold the line - 3Each soldier's index counts strictly shorter soldiers on both sides; output the leftmost start of a length-k window with the maximal index sum.	Medium4	Prefix sumSliding window+1	No attempts yet	2s	1024 MB	Judgeable
Gagarin CupGiven per-venue win probabilities for two teams in a first-to-four series with a 2-2-1-1-1 schedule, find the chance the series ends with a given score.	Medium4	ProbabilityDynamic programming	No attempts yet	2s	1024 MB	Judgeable
Backup SystemSimulate a backup system on a lowercase string: when a character repeats, output the suffix after its last occurrence as a backup, then print the final string.	Medium4	SimulationStack+1	No attempts yet	2s	1024 MB	Judgeable
Martian FriendGiven N and k, count how many trailing zeros N! has when written in base k.	Medium4	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
JourneyGiven taken seats and the seats Lida wants (out of 54), find the fewest ticket ranges that buy every wanted seat without buying any unwanted free seat.	Medium4	GreedyImplementation	No attempts yet	2s	1024 MB	Judgeable
Electronic ClockFind the fewest seconds needed to turn the start time into the target time, where each press adds one minute after a delay of l seconds.	Medium4	ImplementationMath+1	No attempts yet	2s	1024 MB	Judgeable
Super Massive Black HoleGiven n black holes with masses w_i and a deadline D, find the minimum total cost to produce one per day and move each to day D.	Medium4	SortingDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
PlaylistDecide whether the first song can be playing at second T when the shuffle plays every song once per round in random order.	Medium4	Dynamic programmingImplementation	No attempts yet	2s	1024 MB	Judgeable
RoadsGiven unit roads on an integer grid, find the fewest new unit roads that make the mayor's home-to-city-hall trip as short as possible.	Medium4	Shortest pathBFS+1	No attempts yet	2s	1024 MB	Judgeable
Card TrickGiven n and m, find the minimum number of deals that always brings the chosen card to the top, which equals the count of base-m digits of n-1.	Medium4	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
CrossroadGiven N cars arriving at a four-way intersection with main-road sides a and b, the task is to find the time each car passes under the yielding rules.	Medium4	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Chemical CipherGiven a cipher string and a list of element symbols, find the fewest symbols whose concatenation contains the cipher as a subsequence, or -1 if none exists.	Medium4	Dynamic programmingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Glue!Given a grid of piece labels, check that every label covers exactly k cells and that each piece is connected through shared sides.	Medium4	BFSHash map+1	No attempts yet	2s	1024 MB	Judgeable
TreeCount the red and green colorings of a rooted tree's edges where each vertex has at most one red edge from its children, modulo 10^9 + 7.	Medium4	TreeDynamic programming	No attempts yet	2s	1024 MB	Judgeable
VasyaCheck whether a recorded rooftop walk is valid, simulating jumps and moves, and report the final building or the first failing action.	Medium4	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Wipe it!Simulate a teacher writing a word one letter at a time, wiping each suffix that already appears elsewhere in the word, and output the final word on the board.	Medium4	StringString matching+1	No attempts yet	2s	1024 MB	Judgeable
Brick towersGiven n tower heights and a target k, find the longest run of consecutive towers whose average height is exactly k, and output its length and start index.	Medium4	Prefix sumHash map+1	No attempts yet	2s	1024 MB	Judgeable
CubesGiven strings of A and B cubes, decide whether each line can be split into single A cubes and adjacent AB or BA bricks.	Medium4	StringGreedy	No attempts yet	2s	1024 MB	Judgeable
The Most Global Positioning SystemGiven three non-collinear tower positions and the distance from each tower to an object, find the object's coordinates, or print Impossible if no point fits.	Medium4	GeometryMath	No attempts yet	2s	1024 MB	Judgeable
Diligent BeaversGiven ten rules for a beaver moving along an infinite row of trees, decide whether the beaver can become happy starting from the angry mood.	Medium4	GraphBFS	No attempts yet	2s	1024 MB	Judgeable
ExponentiationGiven k, count the pairs (a, b) with a at least 2 and b at least 1 such that a^b has exactly k decimal digits.	Medium4	MathBrute force	No attempts yet	2s	1024 MB	Judgeable
Art ClassGiven N cells and Q range queries that paint only still-uncolored cells, print the final color of each cell.	Medium4	Union-findArray	No attempts yet	0.5s	512 MB	Judgeable
PrincipalitiesGiven births and deaths in a family tree, find the living prince who holds the k-th principality in preorder for each query, or print - if too few princes live.	Medium4	DFSTree+1	No attempts yet	2s	1024 MB	Judgeable
Football FormationGiven ten player positions, find all formations the team could have had, where at most two players move between each pair of lines.	Medium4	Brute forceImplementation	No attempts yet	2s	1024 MB	Judgeable
Festive OlympiadGiven n problems with solve times and m teams that work in parallel, find the minimum sum of submission times for all problems.	Medium4	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
AwardsCount ways to pick k non-adjacent employees out of n in a row, modulo a prime m, with n up to 100000.	Medium4	MathCombinatorics	No attempts yet	2s	1024 MB	Judgeable
Big Horse RaceGiven a line through two points and N circles, find the total length of the line covered by at least one circle.	Medium4	GeometrySorting+1	No attempts yet	2s	1024 MB	Judgeable
Advertising PosterEach word of a slogan is placed horizontally or vertically, with no two vertical words in a row, to minimize the longest horizontal word.	Medium4	Dynamic programmingString	No attempts yet	2s	1024 MB	Judgeable
Songi in the Strange HotelGiven the rank N of a room when all room labels are sorted, print the labels of the rooms on the path from that room up to room 1 on floor 1.	Medium4	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Last-minute crammingChoose which problems to solve within T days so that the total fine of the unsolved problems is as small as possible.	Medium4	Dynamic programming	No attempts yet	1s	1024 MB	Judgeable