Interview core

Mediums from real onsites

Under construction

Still being built. Things may change

Total results3,617 problems

Air Cownditioning
Medium5
Array, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Alien Piano
Medium5
Dynamic programming, Greedy+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
High Buildings
Medium5
Greedy, Implementation+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Metal Harvest
Medium5
Greedy, Intervals+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Energy Stones
Medium5
Greedy, Dynamic programming+1
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable
The Equation
Medium5
Bit manipulation, Greedy
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Diagonal Puzzle
Medium5
Graph, BFS
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Even Digits
Medium5
Greedy, Math+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Planet Distance
Medium5
Graph, BFS+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Yogurt
Medium5
Greedy, Sorting+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Algorithm Class - Bubble Sort 1
Medium5
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Bubble Sort 3
Medium5
Sorting, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Big Buttons
Medium5
String, Trie+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Mural
Medium5
Sliding window, Greedy+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Pattern Overlap
Medium5
String, String matching+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Trapezoid Counting
Medium5
Sorting, Combinatorics+1
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable
Kicksort
Medium5
Array, Simulation+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Algorithm Class - Insertion Sort 1
Medium5
Sorting, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Insertion Sort 3
Medium5
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
JOI Poster
Medium5
Divide and conquer, Recursion+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Nile.Com
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mall
Medium5
Prefix sum, Sliding window+2
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Anagram
Medium5
Combinatorics, Math+2
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Moving
Medium5
Backtracking, Matrix
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Elder price robot
Medium5
Stack, Array+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Glitching screen
Medium5
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Live Aid
Medium5
Dynamic programming, Sorting+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Meticulous smoothing
Medium5
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rods
Medium5
Greedy, Brute force+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Report
Medium5
Stack, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Square
Medium5
Dynamic programming, Matrix+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Workshop
Medium5
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
КАРТИ
Medium5
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Coding
Medium5
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Triangles
Medium5
Sorting, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
PALINDROME
Medium5
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pigeon Cells
Medium5
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
ПОДНИЗ
Medium5
String, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Next Number
Medium5
Greedy, String
No attempts yet
Time limit
0.1s
Memory limit
8 MB
Judgeable
Strawberry 2
Medium5
Sliding window, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Egoi Exhibition (EGOI Exhibition)
Medium5
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Algorithm Class - Matrix Path Problem 4
Medium5
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Similar Rhyme Game
Medium5
Trie, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bracket String Notation (Small)
Medium5
Dynamic programming, Math
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Lucky Number Test
Medium5
Implementation, Simulation+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Algorithm Class - Breadth First Search 4
Medium5
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Carpet
Medium5
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Debugging
Medium5
Two pointers, Sliding window+2
No attempts yet
Time limit
0.6s
Memory limit
512 MB
Judgeable
Graph Stem
Medium5
Tree, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Feeding Duksu
Medium5
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Depth-First Search 6
Medium5
DFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
blobaww
Medium5
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
blobhyperthink
Medium5
Dynamic programming, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
queuestack
Medium5
Queue, Stack+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Abridged Reading
Medium5
Tree, DFS+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Recycling
Medium5
Stack, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bracket Pairing
Medium5
Dynamic programming, String+2
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Parking Lot
Medium5
Shortest path, Geometry+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Tournament Seeding
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Photoshoot 2
Medium5
Array, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dijamant
Medium5
Matrix, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Pawn Shop
Medium5
Hash map, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Protect the Pollen!
Medium5
Tree, Dynamic programming
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
RSA Mistake
Medium5
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Slide Count
Medium5
Two pointers, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
First Orchard
Medium5
Probability, Dynamic programming
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Robot Turtles
Medium5
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Traveling Monk
Medium5
Binary search, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pharmacy
Medium5
Simulation, Heap+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Field Trip
Medium5
Prefix sum, Binary search
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
I.O.U.
Medium5
Graph, DFS
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Annoyed Coworkers
Medium5
Binary search, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jack The Lumberjack
Medium5
Sorting, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Air Conditioner
Medium5
Intervals, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Third Group Exam
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Numbers
Medium5
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Word Magic Square
Medium5
Backtracking, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Inversions Organize
Medium5
Math, Matrix+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Ordinary Ordinals
Medium5
Math, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Distributing Kits
Medium5
Prefix sum, Array+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
줄넘기
Medium5
Hash map, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Lottery Fun Time
Medium5
Hash map, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Visits
Medium5
Graph, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Most Ordered Way
Medium5
Greedy, Sorting
No attempts yet
Time limit
0.3s
Memory limit
1024 MB
Judgeable
Well Off
Medium5
Graph, DFS
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Icing
Medium5
Graph, BFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
LAN Cable Connection
Medium5
Dynamic programming, Math
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Best Edge
Medium5
Shortest path, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Evolution of Weasels
Medium5
String, Greedy
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Boundary
Medium5
Number theory, Brute force
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Longest straight from dice
Medium5
Greedy, Sorting
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Subarray Score Sum
Medium5
Sliding window, Hash map+1
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Letter Blocks
Medium5
Greedy, String+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Even Stronger
Medium5
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
KLIZA
Medium5
BFS, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kryptonite
Medium5
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ari's Cheerful Outing
Medium5
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Meticulous Kuki's Graduation Trip
Medium5
Graph, Union-find
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Clean Water of Mount Piat
Medium5
Sorting, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gomgomi's Errand
Medium5
Tree, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Air CownditioningGiven preferred and current temperatures per stall, find the minimum number of range-increment or range-decrement commands to reach the target.	Medium5	ArrayGreedy+2	No attempts yet	2s	1024 MB	Judgeable
Alien PianoGiven a sequence of pitches, assign each to one of 4 ordered keys so that relative comparisons are preserved as often as possible, minimizing rule breaks.	Medium5	Dynamic programmingGreedy+2	No attempts yet	Not set	1024 MB	Judgeable
High BuildingsConstruct heights for N buildings so that exactly A are visible from the left, B from the right, and C from both, or report that no such heights exist.	Medium5	GreedyImplementation+1	No attempts yet	20s	1024 MB	Judgeable
Metal HarvestGiven sorted non-overlapping harvesting intervals and a maximum deployment length K, find the minimum number of robots needed so every allowed time unit is harvested.	Medium5	GreedyIntervals+2	No attempts yet	20s	1024 MB	Judgeable
Energy StonesGiven each stone's eating time, starting energy, and per-second decay, find the maximum total energy Duda can receive by choosing which stones to eat and in what order.	Medium5	GreedyDynamic programming+1	No attempts yet	30s	1024 MB	Judgeable
The EquationGiven N integers and a limit M, find the largest k such that the sum of each A_i XOR k is at most M, or report -1 if no k works.	Medium5	Bit manipulationGreedy	No attempts yet	15s	1024 MB	Judgeable
Diagonal PuzzleGiven an N by N grid of black and white squares, find the fewest diagonal flips that turn every square black.	Medium5	GraphBFS	No attempts yet	20s	1024 MB	Judgeable
Even DigitsGiven an integer N, find the minimum number of +1/-1 steps to reach a number whose decimal digits are all even.	Medium5	GreedyMath+2	No attempts yet	20s	1024 MB	Judgeable
Planet DistanceIn a connected graph with exactly one cycle, find each node's distance to the nearest node on that unique cycle.	Medium5	GraphBFS+2	No attempts yet	20s	1024 MB	Judgeable
YogurtEach yogurt cup expires A_i days from today and cannot be eaten on or after that day; with at most K cups eaten per day, find the maximum number of cups Lucy can consume starting today.	Medium5	GreedySorting+2	No attempts yet	20s	1024 MB	Judgeable
Algorithm Class - Bubble Sort 1Given an array and a swap count K, report the two values swapped by the K-th exchange in the given bubble sort, or -1 if fewer than K swaps occur.	Medium5	SimulationSorting+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Bubble Sort 3Given distinct arrays A and B, decide whether bubble sort run on A reaches a state equal to B at some point, including the initial state.	Medium5	SortingImplementation+2	No attempts yet	1s	512 MB	Judgeable
Big ButtonsCount the length-N strings over {R,B} that do not start with any of P given forbidden prefixes, where some prefixes may contain others.	Medium5	StringTrie+2	No attempts yet	20s	1024 MB	Judgeable
MuralGiven a digit string of wall beauty scores, find the maximum total beauty Thanh can guarantee when each day he paints a section adjacent to painted ones and an unpainted end section crumbles.	Medium5	Sliding windowGreedy+2	No attempts yet	20s	1024 MB	Judgeable
Pattern OverlapGiven two patterns where each star matches 0 to 4 letters, decide whether some title matches both patterns.	Medium5	StringString matching+1	No attempts yet	Not set	1024 MB	Judgeable
Trapezoid CountingGiven stick lengths, count the sets of four sticks that can form an isosceles trapezoid with exactly one pair of parallel sides.	Medium5	SortingCombinatorics+1	No attempts yet	30s	1024 MB	Judgeable
KicksortGiven a permutation of 1..N, decide whether every pivot Kicksort picks during its recursion is a worst-case pivot.	Medium5	ArraySimulation+2	No attempts yet	Not set	1024 MB	Judgeable
Algorithm Class - Insertion Sort 1Simulate insertion sort on N distinct integers, track each element write, and print the value written on the K-th store or -1 if there are fewer than K writes.	Medium5	SortingSimulation+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Insertion Sort 3Simulate insertion sort on array A and print 1 if the array ever equals B during the process, otherwise 0.	Medium5	SimulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
JOI PosterGiven N and K, print row K of a recursively defined 2^N by 2^N poster built from J, O, and I quadrants.	Medium5	Divide and conquerRecursion+2	No attempts yet	1s	1024 MB	Judgeable
Nile.ComChoose one of N stores each day for D days to minimize total cost, with 10% off for a store used two days in a row and 30% off for three or more.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
MallIn an m by n grid where some blocks are blocked, find the a by b all-free rectangle with the smallest sum of block costs.	Medium5	Prefix sumSliding window+2	No attempts yet	6s	1024 MB	Judgeable
AnagramGiven a string of up to 20 uppercase letters, find its 1-based lexicographic rank among all distinct permutations of its characters.	Medium5	CombinatoricsMath+2	No attempts yet	0.5s	1024 MB	Judgeable
MovingCount the ways to cover every floor cell of an H by W grid with non-overlapping L-shaped carpets of 3 cells, where walls cannot be covered.	Medium5	BacktrackingMatrix	No attempts yet	8s	1024 MB	Judgeable
Elder price robotFor each day, report how many days back the price was last lower than or equal to today's price, or infinity if no earlier price was that low.	Medium5	StackArray+2	No attempts yet	4s	1024 MB	Judgeable
Glitching screenGiven n candidate h by w pixel renderings and a current screen that may have dead pixels stuck off, decide whether exactly one stop matches.	Medium5	StringImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Live AidGiven n musicians, each with a start time, end time, and attention value, choose a non-overlapping subset that maximizes total attention.	Medium5	Dynamic programmingSorting+2	No attempts yet	3s	1024 MB	Judgeable
Meticulous smoothingGiven a plank's thickness at n positions, shave off 1 micrometer at a time so that neighboring thicknesses differ by at most 1; find the minimum number of shaves.	Medium5	Dynamic programmingGreedy+2	No attempts yet	1s	1024 MB	Judgeable
RodsGiven three rod lengths with limited counts of each, find the fewest rods whose total length reaches at least L, or print 0 if impossible.	Medium5	GreedyBrute force+2	No attempts yet	1s	1024 MB	Judgeable
ReportFor each day, find the nearest earlier day whose income is smaller; print its index, or 0 if none exists.	Medium5	StackArray+2	No attempts yet	1s	1024 MB	Judgeable
SquareGiven a table of 0s and 1s, find the largest odd side length of a square whose two diagonals contain only 1s.	Medium5	Dynamic programmingMatrix+1	No attempts yet	2.5s	1024 MB	Judgeable
WorkshopGiven n parts and two identical machines, decide whether all parts can be scheduled on the two machines within a total time limit T.	Medium5	Dynamic programmingGreedy+2	No attempts yet	1s	1024 MB	Judgeable
КАРТИGiven four integers (each up to 9999), arrange them in some order and concatenate so the resulting number is as large as possible.	Medium5	SortingGreedy+2	No attempts yet	1s	1024 MB	Judgeable
CodingCount how many distinct strings result from replacing some non-overlapping adjacent digit pairs (values 10 to 10+n-1) with letters a to z.	Medium5	Dynamic programmingString+2	No attempts yet	1s	1024 MB	Judgeable
TrianglesCount triples of segments, one of each color, that satisfy the strict triangle inequality on their lengths.	Medium5	SortingTwo pointers+2	No attempts yet	1s	1024 MB	Judgeable
PALINDROMEGiven a non-palindrome string, find the minimum length after prepending letters to make it a palindrome.	Medium5	StringString matching+2	No attempts yet	1s	1024 MB	Judgeable
Pigeon CellsPlace K pigeons in N cells to maximize the smallest gap between neighbors, then count how many adjacent pairs achieve that smallest gap.	Medium5	MathGreedy+2	No attempts yet	1s	1024 MB	Judgeable
ПОДНИЗFind the longest string that can appear as a substring of some permutation of a and of some permutation of b, breaking ties by lexicographic order.	Medium5	StringGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Next NumberGiven a non-negative integer A, find the smallest integer greater than A whose digits are all different, or report -1 if none exists.	Medium5	GreedyString	No attempts yet	0.1s	8 MB	Judgeable
Strawberry 2Place a 3x3 square on a huge grid and maximize the number of given points it covers.	Medium5	Sliding windowSorting+2	No attempts yet	1s	1024 MB	Judgeable
Egoi Exhibition (EGOI Exhibition)Choose a subset of the paintings in a row, keeping the order, so no two adjacent kept paintings share a type, maximizing the sum of their values.	Medium5	Dynamic programmingArray+2	No attempts yet	1s	1024 MB	Judgeable
Algorithm Class - Matrix Path Problem 4In an n by n grid moving only right or down, find the maximum path score from top-left to bottom-right that visits at least one of P given cells.	Medium5	Dynamic programmingMatrix+2	No attempts yet	1s	512 MB	Judgeable
Similar Rhyme GameGiven n distinct words, pair them up so that each pair shares a common suffix of length at least F, maximizing the number of pairs.	Medium5	TrieGreedy+2	No attempts yet	1s	512 MB	Judgeable
Bracket String Notation (Small)Given N, find the shortest bracket string whose value is N, breaking length ties by lexicographic order.	Medium5	Dynamic programmingMath	No attempts yet	1.5s	1024 MB	Judgeable
Lucky Number TestPrecompute the lucky numbers up to 1,000,000 by repeatedly sieving out elements at multiples of the current pick, then answer each query.	Medium5	ImplementationSimulation+2	No attempts yet	3s	1024 MB	Judgeable
Algorithm Class - Breadth First Search 4Run a BFS from vertex R with neighbors visited in ascending order, then sum depth times visit order over all vertices.	Medium5	BFSGraph+2	No attempts yet	1s	512 MB	Judgeable
CarpetOn a grid of white and black cells, move from top-left to bottom-right stepping only onto adjacent cells of the opposite color, and report the minimum number of moves or -1 if unreachable.	Medium5	BFSGraph+2	No attempts yet	2s	1024 MB	Judgeable
DebuggingGiven M error line numbers in N lines, find the most errors an editor can auto-fix after Ingyu manually fixes at least Y errors, where the editor triggers on any X consecutive clean lines.	Medium5	Two pointersSliding window+2	No attempts yet	0.6s	512 MB	Judgeable
Graph StemGiven a tree, repeatedly strip all leaves at once until two or fewer leaves remain, then output the surviving vertices in ascending order.	Medium5	TreeGraph+2	No attempts yet	1s	512 MB	Judgeable
Feeding DuksuCount the length-N sequences over four restaurants plus a skip state where you never revisit today's restaurant or its neighbors tomorrow, and a skip forces eating the next day.	Medium5	Dynamic programmingCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Depth-First Search 6Run an iterative DFS from R visiting neighbors in descending order, record each vertex's depth and visit order, and sum depth times visit order over all vertices.	Medium5	DFSGraph+2	No attempts yet	1s	512 MB	Judgeable
blobawwCount triples of cells forming the letters E, S, M in a grid so that both row and column indices are nondecreasing, modulo 1e9+7.	Medium5	Dynamic programmingPrefix sum+2	No attempts yet	2s	1024 MB	Judgeable
blobhyperthinkCount the strictly increasing subsequences of length 11 in sequence A, modulo 10^9+7.	Medium5	Dynamic programmingPrefix sum	No attempts yet	2s	1024 MB	Judgeable
queuestackEach of N positions is a queue or stack holding one value; insert M values one at a time and print the value that exits the end of the line.	Medium5	QueueStack+2	No attempts yet	1s	1024 MB	Judgeable
Abridged ReadingGiven page counts and prerequisite edges forming a forest rooted at chapters with no dependents, find the two roots whose combined prerequisite closure has the smallest total page count.	Medium5	TreeDFS+2	No attempts yet	4s	1024 MB	Judgeable
RecyclingFind the contiguous range of weeks and bin capacity that maximize capacity times weeks, where every week in the range has at least that much material.	Medium5	StackArray	No attempts yet	2s	1024 MB	Judgeable
Bracket PairingGiven a bracket string of length up to 20 with some positions unknown, count how many ways to fill the unknowns so the whole sequence becomes a valid bracket sequence over four bracket types.	Medium5	Dynamic programmingString+2	No attempts yet	7s	1024 MB	Judgeable
Parking LotFind the shortest walk from the top-left to the bottom-right corner of a parking lot, where empty spots can be crossed diagonally and car spots only along their edges.	Medium5	Shortest pathGeometry+1	No attempts yet	5s	1024 MB	Judgeable
Tournament SeedingGiven 2^n player ratings and a threshold k, find the maximum number of close games in a seeded single-elimination bracket where higher ratings always win.	Medium5	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Photoshoot 2Given a start permutation and a target permutation, count the fewest cows you must move left (one at a time) to reach the target order.	Medium5	ArrayGreedy+2	No attempts yet	2s	1024 MB	Judgeable
DijamantCount the diamonds in an n by m table of '.' and '#' characters, where each diamond has a border of '#' and an interior of only '.'.	Medium5	MatrixDynamic programming+1	No attempts yet	1s	512 MB	Judgeable
Pawn ShopSplit the rearranged sequence b into as many consecutive groups as possible so that each group holds the same multiset of values as the same positions in a.	Medium5	Hash mapGreedy	No attempts yet	2s	1024 MB	Judgeable
Protect the Pollen!Choose flower families so that no two adjacent flowers in the tree are both chosen, with at most S bees total, maximizing total pollination power.	Medium5	TreeDynamic programming	No attempts yet	5s	1024 MB	Judgeable
RSA MistakeGiven A and B, output full credit if they are distinct primes, partial credit if A*B has no square factor k^2 with k at least 2, otherwise no credit.	Medium5	MathNumber theory	No attempts yet	1s	1024 MB	Judgeable
Slide CountGiven an array and a constant C, count for each element how many distinct windows produced by a two-pointer scan contain it.	Medium5	Two pointersSliding window+1	No attempts yet	1s	1024 MB	Judgeable
First OrchardGiven the fruit counts on four trees and the raven's path length, compute the probability that players pick every fruit before the raven reaches the orchard.	Medium5	ProbabilityDynamic programming	No attempts yet	6s	1024 MB	Judgeable
Robot TurtlesFind the shortest F, R, L, X program that moves the turtle from the bottom-left corner to the diamond on an 8x8 board with rock and ice castles.	Medium5	BFSSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Traveling MonkGiven the monk's ascent and descent segments on the same path, find the earliest time both trips put him at the same elevation.	Medium5	Binary searchSimulation	No attempts yet	2s	1024 MB	Judgeable
PharmacySimulate T technicians filling prescriptions where in-store orders go before remote ones, and output the average completion time for each type.	Medium5	SimulationHeap+1	No attempts yet	3s	1024 MB	Judgeable
Field TripSplit class sections 1 to N into three contiguous groups so that no teacher rides a bus, printing the split points i and j or -1 if impossible.	Medium5	Prefix sumBinary search	No attempts yet	3s	1024 MB	Judgeable
I.O.U.Given a list of I.O.U. debts between friends, cancel every debt cycle by its minimum amount and output the debts that remain.	Medium5	GraphDFS	No attempts yet	3s	1024 MB	Judgeable
Annoyed CoworkersGiven h help requests and coworkers whose annoyance starts at a and rises by d per ask, find the minimum possible maximum annoyance across all coworkers.	Medium5	Binary searchMath+1	No attempts yet	2s	1024 MB	Judgeable
Jack The LumberjackGiven N tree species that are planted, grow linearly for Y years, then shrink, find the maximum total number of trees alive in any single year.	Medium5	SortingSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Air ConditionerDecide whether an air conditioner that can heat, cool, or stay off, starting at temperature m, keeps every customer's temperature at visit time within their range.	Medium5	IntervalsGreedy	No attempts yet	1s	256 MB	Judgeable
Third Group ExamGiven per-block theory grades x_i and practice grades y_i, pick at least a theory blocks and at least b practice blocks to maximize the total grade, and print the choice.	Medium5	GreedySorting	No attempts yet	1s	512 MB	Judgeable
NumbersGiven x and a mood flag, find the smallest y at least x whose digits are all equal, or all equal except one digit when the flag is 1.	Medium5	Brute forceImplementation+1	No attempts yet	1s	512 MB	Judgeable
Word Magic SquarePick L of the N given words to form an L by L square whose rows and columns read the same, choosing the smallest dictionary order, or print NONE.	Medium5	BacktrackingHash map+1	No attempts yet	2s	1024 MB	Judgeable
Inversions OrganizeGiven a 2N by 2N grid of I and O letters, find the fewest cell flips so the top and bottom halves have equal I counts and the left and right halves do too.	Medium5	MathMatrix+1	No attempts yet	20s	1024 MB	Judgeable
Ordinary OrdinalsGiven N and M, find how many brace and comma characters write the set representation of N, modulo M, for N below 2^63.	Medium5	MathDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Distributing KitsGiven N rooms holding A_i kits each, find the fewest single-kit passes between adjacent rooms needed to make every room hold the average count.	Medium5	Prefix sumArray+1	No attempts yet	1s	256 MB	Judgeable
줄넘기For each query range [l, r], find the longest segment whose two ends have equal heights and no student in between has that same height, or print 0.	Medium5	Hash mapSorting+1	No attempts yet	2s	256 MB	Judgeable
Lottery Fun TimePick one first prize ticket, one four-digit second prize suffix, and up to three two-digit third prize suffixes to maximize total winnings.	Medium5	Hash mapBrute force+1	No attempts yet	2s	1024 MB	Judgeable
VisitsEach buddy i wants to visit a_i and gets v_i moos for a visit. Find the maximum total moos over all visiting orders p.	Medium5	GraphImplementation	No attempts yet	2s	1024 MB	Judgeable
Most Ordered WayOrder N tasks with times T and deadlines D so each finishes on time, choosing the lexicographically smallest order, or print * if impossible.	Medium5	GreedySorting	No attempts yet	0.3s	1024 MB	Judgeable
Well OffGiven pairwise inequalities of the form plus or minus x_i plus or minus x_j greater than 0, decide whether some assignment of fortunes satisfies all of them.	Medium5	GraphDFS	No attempts yet	2s	128 MB	Judgeable
IcingGiven battle records as edges, count the smallest sets of at most two edges whose deletion makes the graph bipartite, or return 0 if none exists.	Medium5	GraphBFS+1	No attempts yet	3s	1024 MB	Judgeable
LAN Cable ConnectionChoose a nonempty set of switches with minimum total cost so their ports exactly fit M computers plus one uplink cable, or report -1 if impossible.	Medium5	Dynamic programmingMath	No attempts yet	1.5s	1024 MB	Judgeable
Best EdgeGiven a directed weighted graph with unique shortest paths, find the edges that lie on the most shortest paths between vertex pairs and print their numbers.	Medium5	Shortest pathGraph+2	No attempts yet	2s	1024 MB	Judgeable
Evolution of WeaselsGiven two DNA strings over A, B, and C, decide whether inserting or deleting AA, BB, CC, ABAB, or BCBC can turn one into the other.	Medium5	StringGreedy	No attempts yet	2s	2048 MB	Judgeable
BoundaryGiven a w by l bathroom, find every tile length a for which 1 by a boundary tiles and 1 by 1 interior tiles exactly cover the floor.	Medium5	Number theoryBrute force	No attempts yet	2s	2048 MB	Judgeable
Longest straight from diceGiven dice with S_i sides each, find the most dice that can each show one number in a run of consecutive integers.	Medium5	GreedySorting	No attempts yet	Not set	1024 MB	Judgeable
Subarray Score SumFor each test case, sum i^len + j^len over every subarray A[i, j] of length 2 or more with all distinct values, modulo 1e9+7.	Medium5	Sliding windowHash map+1	No attempts yet	1.5s	512 MB	Judgeable
Letter BlocksGiven several towers of letter blocks, stack them all into one megatower where each letter forms a single contiguous group, or report IMPOSSIBLE.	Medium5	GreedyString+1	No attempts yet	5s	1024 MB	Judgeable
Even StrongerPick which villages to recruit at minimum gold so that the towers' archers can hit at least k soldiers along the path.	Medium5	Dynamic programming	No attempts yet	1s	1024 MB	Judgeable
KLIZAGiven a 3x3 sliding puzzle, find the fewest moves to reach the solved grid and print the tile moved into the blank cell at each step.	Medium5	BFSGraph	No attempts yet	1s	1024 MB	Judgeable
KryptoniteFind a down/right path from the top-left to the bottom or right edge minimizing the sum of Chebyshev-distance-K neighborhood weights at each visited cell.	Medium5	Dynamic programmingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Ari's Cheerful OutingFind the most tasks Ari can finish along a right, down, or diagonal grid path from corner to corner within T minutes.	Medium5	Dynamic programmingMatrix	No attempts yet	1s	1024 MB	Judgeable
Meticulous Kuki's Graduation TripAfter each sight is removed in order, determine whether the remaining graph is still connected, checking the initial graph too.	Medium5	GraphUnion-find	No attempts yet	2s	512 MB	Judgeable
Clean Water of Mount PiatChoose the most hikers who can drink in some order, each with a threshold above the contamination at their turn, and minimize the final level.	Medium5	SortingDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Gomgomi's ErrandGiven a tree and the route S to C to H, count the ordered pairs of distinct cities where Gomgomi can buy two chicken legs in order.	Medium5	TreeBFS+1	No attempts yet	1s	1024 MB	Judgeable