Problems

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Total results29,450 problems

Rest Stops
Medium5
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Milking Order
Medium5
Topological sort, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Family Tree
Medium5
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
QueryreuQ
Medium5
String, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Zigzag Sequence
Medium5
Array, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Counting the closest pair sums
Medium5
Sorting, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Miss That Bus and You Are Late!!
Medium5
Simulation, Queue+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
*Light*Young*Woo*
Medium5
Geometry, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Warring States
Medium5
Union-find, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Balloon Factory
Medium5
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Drain Pipes
Medium5
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ah-Choo!
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Martian DNA
Medium5
Sliding window, Array+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pen Pineapple Apple Pen
Medium5
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
&+ +&
Medium5
Bit manipulation, Math+1
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Card merge game
Medium5
Greedy, Heap+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gahui the Grappler!!
Medium5
Geometry, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Uks Is an Apple Fan!!
Medium5
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dolls
Medium5
Brute force, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rotating Sushi
Medium5
Sliding window, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Longest Consecutive Subsequence
Medium5
Dynamic programming, Hash map+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Evakum
Medium5
Prefix sum, Array+2
No attempts yet
Time limit
1.5s
Memory limit
256 MB
Judgeable
Water Tank
Medium5
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Teacher
Medium5
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Meditation Disturber
Medium5
Prefix sum, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
1, 2, 3 Sum 5
Medium5
Dynamic programming, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
1, 2, 3 Addition 7
Medium5
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
0.25s
Memory limit
512 MB
Judgeable
Missing Gnomes
Medium5
Greedy, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pants On Fire
Medium5
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Attack on Alpha-Zet
Medium5
Tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Finding Your Coach
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Life on a Torus
Medium5
Simulation, Hash map+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Catan's Longest Road
Medium5
Backtracking, Graph+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Extending Rock-Paper-Scissors
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
5th Job Advancement
Medium5
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Signal
Medium5
Implementation, Array+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Arrow Operator
Medium5
Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
PPAP
Medium5
Stack, String+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Demerit Points (DemeritPoints)
Medium5
Simulation, String+2
No attempts yet
Time limit
0.1s
Memory limit
32 MB
Judgeable
Engineering Calculator
Medium5
Recursion, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Drawing
Medium5
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Non-Violent Protests
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Blog
Medium5
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Longest Increasing Palindromic Subsequence
Medium5
String, Two pointers+1
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
A Great Way
Medium5
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Execution Time
Medium5
Dynamic programming, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
I Have Few Friends (Large)
Medium5
String matching, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jumping King Jelly (Small)
Medium5
DFS, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Why is Math Book So Sad?
Medium5
Math, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Adding 1, 2, 3 (9)
Medium5
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Two Coins
Medium5
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rectangles
Medium5
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
DSHS Bank
Medium5
Math, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
GCC Min Max Expression
Medium5
Stack, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Math Problem
Medium5
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Population Movement
Medium5
Simulation, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Magic Weapon
Medium5
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bit Palindromic Numbers
Medium5
Math, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Passport Control
Medium5
Queue, Stack+2
No attempts yet
Time limit
0.2s
Memory limit
512 MB
Judgeable
H to O
Medium5
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
A Prize No One Can Win
Medium5
Array, Sorting+2
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Fishermen
Medium5
Array, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Die
Medium5
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Flute
Medium5
Implementation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Sheba's Amoebas
Medium5
DFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sharing the Snacks
Medium5
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Amusement Park
Medium5
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Seungbeom Corporation
Medium5
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Illiteracy
Medium5
BFS, Graph+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Inversions
Medium5
Array, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Area Rug
Medium5
Prefix sum, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Judy and the Carrot Farm
Medium5
Implementation, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sheep Rescue Operation
Medium5
Tree, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Chicken Chicken Chicken
Medium5
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jake and Cake
Medium5
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dual Channel VHF Radio
Medium5
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gazua
Medium5
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bookend
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Making a Palindrome
Medium5
String matching, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Meet at One Point!
Medium5
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Small Penalty
Medium5
Sorting, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Pokegene
Medium5
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Lipschitz Constant
Medium5
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Building a Field
Medium5
Hash map, Geometry+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cheap Trips
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Erdös-Straus Conjecture
Medium5
Math, Number theory+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Friendship Fee
Medium5
Union-find, Graph+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Edit Distance
Medium5
String, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Binary String
Medium5
String, Greedy+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Achievements
Medium5
Two pointers, Array+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hard Drive
Medium5
Greedy, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Kleptography
Medium5
Array, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Left and Right
Medium5
Greedy, Stack+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Building a Symmetric Stair
Medium5
Math, Implementation+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Email Destruction
Medium5
String, Hash map+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Guest Student
Medium5
Array, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
JS Minification
Medium5
String, Simulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Geunwoo's Diary Decorating
Medium5
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Defile
Medium5
Greedy, Sorting
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
House Numbers
Medium5
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Rest StopsBessie rests at grass stops along a trail and must never fall behind Farmer John; maximize total tastiness of eaten grass.	Medium5	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
Milking OrderGiven a partial order between some cows and fixed positions for others, find the earliest position cow 1 can occupy.	Medium5	Topological sortGreedy+2	No attempts yet	2s	512 MB	Judgeable
Family TreeGiven a set of mother-child pairs, classify the relationship between two cows as siblings, direct ancestor, aunt, cousins, or unrelated, following a fixed rule order.	Medium5	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
QueryreuQMaintain a string under append and pop-back operations, and after each operation print the number of palindromic substrings it contains.	Medium5	StringDynamic programming+2	No attempts yet	1s	1024 MB	Judgeable
Zigzag SequenceGiven a sequence, find the longest contiguous block in which no three consecutive terms are monotone increasing or monotone decreasing.	Medium5	ArrayTwo pointers+2	No attempts yet	1s	1024 MB	Judgeable
Counting the closest pair sumsGiven n integers and a target v, count how many index pairs have a sum whose distance from v is as small as possible.	Medium5	SortingTwo pointers+2	No attempts yet	2s	512 MB	Judgeable
Miss That Bus and You Are Late!!Simulate a single-lane bus stop where each bus parks in the frontmost free spot, waits if a bus ahead is still parked, and departs after its dwell time; report the parking spot of the m-th bus.	Medium5	SimulationQueue+1	No attempts yet	1s	512 MB	Judgeable
LightYoungWooGiven N lights that each illuminate a 90-degree upward sector, count for each query point how many sectors contain it.	Medium5	GeometryPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
Warring StatesProcess alliance and war records between groups, merging by sum for alliances and subtracting troops for wars, then report surviving groups sorted by troop count.	Medium5	Union-findImplementation+2	No attempts yet	1s	128 MB	Judgeable
Balloon FactoryFind the minimum time for N workers, each producing one balloon every A_i minutes, to finish M balloons in parallel.	Medium5	Binary searchGreedy+2	No attempts yet	1s	256 MB	Judgeable
Drain PipesCount the number of ways to pick quantities of each pipe type, within the given stock, so the chosen pipes sum to exactly x.	Medium5	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
Ah-Choo!Compute the least Dynamic Time Warping distance between two equal-length integer sequences, where every point must match at least one point of the other and matches cannot cross.	Medium5	Dynamic programmingArray+1	No attempts yet	1s	512 MB	Judgeable
Martian DNAGiven a string over K symbols and minimum counts for R of them, find the length of the shortest contiguous substring meeting all the quotas, or report impossible.	Medium5	Sliding windowArray+2	No attempts yet	2s	1024 MB	Judgeable
Pen Pineapple Apple PenGiven a string of A, P, and p, find the maximum number of disjoint subsequence occurrences of the pattern p, P, A, p in order.	Medium5	GreedyString+1	No attempts yet	1s	32 MB	Judgeable
&+ +&Over all N^2 pairs, compute the sum modulo 1999 of pairwise ANDs, and the bitwise AND of all pairwise sums.	Medium5	Bit manipulationMath+1	No attempts yet	1.5s	512 MB	Judgeable
Card merge gameEach merge replaces two chosen cards with their sum; after exactly m merges, minimize the total sum of all cards.	Medium5	GreedyHeap+2	No attempts yet	1s	512 MB	Judgeable
Gahui the Grappler!!Given a piecewise linear function through points (i, y_i) with y_0=0, decide whether the ray y=kx meets it anywhere besides the origin.	Medium5	GeometryMath+2	No attempts yet	2s	512 MB	Judgeable
Uks Is an Apple Fan!!Count the number of paths on an N by M grid where each cell directs movement right, down, or both, and every path must end at cell (N, M).	Medium5	Dynamic programmingCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
DollsGiven N numbers in a fixed order, find a contiguous segment of at least K numbers whose standard deviation is minimized, and output that standard deviation.	Medium5	Brute forcePrefix sum+2	No attempts yet	1s	512 MB	Judgeable
Rotating SushiOn a circular belt of N sushi plates, find the maximum number of distinct kinds in any k consecutive plates, counting the coupon kind c once more if it is not already present.	Medium5	Sliding windowTwo pointers+2	No attempts yet	1s	512 MB	Judgeable
Longest Consecutive SubsequenceGiven an integer sequence, find the longest subsequence whose values form an arithmetic run with common difference 1, keeping the original order.	Medium5	Dynamic programmingHash map+1	No attempts yet	2s	256 MB	Judgeable
EvakumMaintain an array with range-add updates and range-sum queries, answering the queries in the order given.	Medium5	Prefix sumArray+2	No attempts yet	1.5s	256 MB	Judgeable
Water TankGiven a grid of tank cells with holes in their walls, compute the total water volume left after water drains out through the holes.	Medium5	GraphShortest path+1	No attempts yet	2s	512 MB	Judgeable
TeacherStarting at the integer point (0,0), find the minimum number of jumps to reach (M,N), where a jump is allowed between two integer points exactly when the segment joining them contains no other integer point.	Medium5	Number theoryMath+1	No attempts yet	1s	512 MB	Judgeable
Meditation DisturberEach bird on the left or right chirps on some seconds; remove one bird so the peak absolute value of the running signed sum over M seconds is minimized, and report its index and that value.	Medium5	Prefix sumImplementation+2	No attempts yet	2s	512 MB	Judgeable
1, 2, 3 Sum 5Count the ordered sums of 1, 2, and 3 that add to n, with no equal value adjacent, modulo 1,000,000,009.	Medium5	Dynamic programmingMath+2	No attempts yet	1s	512 MB	Judgeable
1, 2, 3 Addition 7Count ordered compositions of n into exactly m parts, where each part is 1, 2, or 3, modulo 1,000,000,009.	Medium5	Dynamic programmingCombinatorics+2	No attempts yet	0.25s	512 MB	Judgeable
Missing GnomesGiven a subsequence of 1..n, find the lexicographically smallest permutation of 1..n that contains it as a subsequence.	Medium5	GreedyImplementation+2	No attempts yet	2s	512 MB	Judgeable
Pants On FireGiven n true statements of the form "a are worse than b" that form a partial order, classify each of m queries as Fact, Alternative Fact, or Pants on Fire by transitive reachability.	Medium5	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Attack on Alpha-ZetGiven an ASCII-drawn perfect maze and a sequence of marked rooms, count the rooms Captain Krys walks through along the route in order.	Medium5	TreeGraph+2	No attempts yet	2s	512 MB	Judgeable
Finding Your CoachGiven your coach number and the coach counts to its left and right, decide whether the ticketed coach is here, certainly left, certainly right, or ambiguous.	Medium5	MathImplementation	No attempts yet	2s	512 MB	Judgeable
Life on a TorusSimulate Conway's Life on a wrapped 8x8 torus and find the smallest repeat period reached after any transient.	Medium5	SimulationHash map+1	No attempts yet	2s	512 MB	Judgeable
Catan's Longest RoadGiven a Catan board where each lane is empty or owned by player 1, 2, or 3, find the longest road each player can build from their own distinct segments.	Medium5	BacktrackingGraph+1	No attempts yet	4s	512 MB	Judgeable
Extending Rock-Paper-ScissorsLabel n elements so every element beats exactly half the others, and print one ordered winner-loser line for each unordered pair.	Medium5	MathImplementation	No attempts yet	2s	512 MB	Judgeable
5th Job AdvancementOrder n quests and toggle at most k active Arcane Stones to split each quest reward among run lengths, maximizing total collected experience.	Medium5	SortingPrefix sum+1	No attempts yet	1s	512 MB	Judgeable
SignalDecode a 5-row pixel strip into digits: 3-column glyphs except 1, separated by blank columns.	Medium5	ImplementationArray+1	No attempts yet	1s	512 MB	Judgeable
Arrow OperatorX equals the number of hyphens in the prefix merger trace: even 1 to 10 have widths 3, 6, 10, 10, 15, 21, 28, 36, 45, 55.	Medium5	Math	No attempts yet	1s	512 MB	Judgeable
PPAPDecide whether a length-1000000 string of P and A is generated from P by replacing a P with PPAP at each step.	Medium5	StackString+1	No attempts yet	1s	512 MB	Judgeable
Demerit Points (DemeritPoints)Simulate a student's demerit events encoded as base-36 chars, tracking accumulated points and quotient-by-10 crossing, and output total expulsion weeks plus weapon or permanent marker.	Medium5	SimulationString+2	No attempts yet	0.1s	32 MB	Judgeable
Engineering CalculatorEvaluate an integer arithmetic expression with precedence, right-associative exponentiation and square root, and truncation toward zero for incomplete roots and divisions.	Medium5	RecursionMath+2	No attempts yet	1s	256 MB	Judgeable
DrawingGiven n brightness values, decide whether some real a and positive real b make floor(a + b*k) equal every value.	Medium5	MathBrute force+2	No attempts yet	1s	256 MB	Judgeable
Non-Violent ProtestsGiven each person's threshold, find how many riot if someone riots once that many others already do.	Medium5	GreedySorting+1	No attempts yet	2s	512 MB	Judgeable
BlogGiven a string of R, G, and B, find the minimum number of contiguous same-color paint operations needed to build it.	Medium5	Dynamic programmingString+2	No attempts yet	1s	256 MB	Judgeable
Longest Increasing Palindromic SubsequenceGiven up to 10^5 integers, find the longest contiguous subarray that is a palindrome whose values strictly rise from both ends toward the center.	Medium5	StringTwo pointers+1	No attempts yet	1.5s	512 MB	Judgeable
A Great WayFind the cheapest path from node 1 to node N, where an edge costs c + d*max(0,e-10), breaking ties by fewer waypoints.	Medium5	GraphShortest path+1	No attempts yet	1s	128 MB	Judgeable
Execution TimeGiven ranks and operating speeds of n computers in a chain of ranks, compute when the whole task finishes using transmission time (i-j)^2 between machines.	Medium5	Dynamic programmingGraph+1	No attempts yet	2s	128 MB	Judgeable
I Have Few Friends (Large)Find whether keyword K appears in S as an exact substring, digits and all, and print 1 or 0.	Medium5	String matchingString+1	No attempts yet	1s	128 MB	Judgeable
Jumping King Jelly (Small)Given an N by N board with jump numbers, move only right or down from the top-left and reach the bottom-right, or report failure.	Medium5	DFSBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Why is Math Book So Sad?For each of up to 10000 queries (A, B, C, D), find nonnegative integers x, y, z satisfying three polynomial equations, choosing the smallest x then smallest y.	Medium5	MathBrute force+2	No attempts yet	2s	512 MB	Judgeable
Adding 1, 2, 3 (9)Count ordered compositions of n into parts 1, 2, and 3 that use at most m terms, and output each count modulo 1,000,000,009.	Medium5	Dynamic programmingCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Two CoinsMove both coins together with four direction buttons and find the shortest press sequence that drops exactly one coin off the board.	Medium5	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
RectanglesChoose pairs of sticks (each possibly shortened by at most 1) as opposite sides of rectangles, maximizing the total area.	Medium5	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
DSHS BankPick the branch minimizing the total taxicab distance to all others, breaking ties by smallest branch number.	Medium5	MathSorting+2	No attempts yet	2s	512 MB	Judgeable
GCC Min Max ExpressionEvaluate an expression containing the <? (min) and >? (max) operators plus + and -, respecting precedence, left associativity, and parentheses.	Medium5	StackImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Math ProblemFor each N, find the smallest X such that N plus the digit sum of X equals X, or report -1 if none exists.	Medium5	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Population MovementRepeat until stable: open borders whose population difference is L to R, compute each connected union's floored mean population, and count the days with any change.	Medium5	SimulationBFS+2	No attempts yet	2s	512 MB	Judgeable
Magic WeaponCount triples of details, one per color, where the red number's first and last digits match the green's last digit and the blue's first digit, and all three model numbers differ.	Medium5	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Bit Palindromic NumbersCount integers in [l, r] whose first and last decimal digits match; solve with per-length counts and digit-DP over 10^18 ranges.	Medium5	MathDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Passport ControlDecide whether a given exit permutation can arise from a FIFO arrival line feeding k desk queues, each holding an arrival-ordered subsequence.	Medium5	QueueStack+2	No attempts yet	0.2s	512 MB	Judgeable
H to OCount each atom's total from the input formula multiplied by k and from the output formula, then divide each element's counts to find the smallest quotient, the output count.	Medium5	StringHash map+2	No attempts yet	1s	512 MB	Judgeable
A Prize No One Can WinPick a largest subset of item prices such that no pair has a sum strictly greater than X, and print its size.	Medium5	ArraySorting+2	No attempts yet	1.5s	512 MB	Judgeable
FishermenCount for each fisherman how many fish satisfy \|x - a\| + y <= l, given fish and fishermen positions on a line.	Medium5	ArraySorting+1	No attempts yet	1s	512 MB	Judgeable
DieClassify a 3x3 grid of o and : as one of the five standard die faces 1-5, up to rotation, or output unknown if it matches none.	Medium5	ImplementationSimulation+2	No attempts yet	2s	512 MB	Judgeable
FluteGiven four scrambled lamp grids whose lit lamps may include burned-out (dark) ones, output the earliest valid time matching each grid as a digit pattern.	Medium5	ImplementationBrute force+1	No attempts yet	1s	512 MB	Judgeable
Sheba's AmoebasCount closed loops of # pixels in an m by n image, where loops may be nested but never touch or overlap.	Medium5	DFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Sharing the SnacksGiven M children and N snack sticks, find the maximum integer length where cutting gives every child one equal piece, or 0 if impossible.	Medium5	Binary searchGreedy+1	No attempts yet	1s	256 MB	Judgeable
Amusement ParkCitizens at various blocks must reach block 0 by taxi (A per block, one rider) or by sharing a bus (B won, up to 40 riders, one pick-up point). Find the minimum total cost.	Medium5	Dynamic programmingSorting+2	No attempts yet	1s	256 MB	Judgeable
Seungbeom CorporationMaintain balances on a company mentor tree while updates add a value to one employee and every employee below them.	Medium5	TreeDFS+1	No attempts yet	1s	256 MB	Judgeable
IlliteracyGiven two 8-icon sequences over A-F where clicking an icon deterministically mutates the whole sequence, find the shortest click sequence turning the start into the target, or -1.	Medium5	BFSGraph+2	No attempts yet	5s	512 MB	Judgeable
InversionsFill each 0 in a length-n sequence with a value from 1 to k so that the number of inversions (pairs i<j with a_i > a_j) is maximized.	Medium5	ArrayDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Area RugCount dirty cells under an s-by-s rug at every placement on an n-by-n grid, then report how many placements cover each possible count.	Medium5	Prefix sumArray+2	No attempts yet	2s	512 MB	Judgeable
Judy and the Carrot FarmPlace as many non-adjacent carrots as possible on an N by N grid given one preset cell, and print the resulting field.	Medium5	ImplementationGreedy+2	No attempts yet	1s	128 MB	Judgeable
Sheep Rescue OperationGiven a tree rooted at 1 with sheep or wolf counts per node, find the maximum number of sheep that can reach node 1 along unique paths while each wolf eats at most one entering sheep.	Medium5	TreeGreedy+2	No attempts yet	1s	256 MB	Judgeable
Chicken Chicken ChickenGiven N members' preference scores for M chicken kinds, choose at most 3 kinds to maximize the sum over members of their highest preference among the chosen kinds.	Medium5	Brute forceImplementation+1	No attempts yet	1s	128 MB	Judgeable
Jake and CakeCut a row cake at the fewest boundaries so each person gets N/4 strawberries and N/4 kiwis, and output one such cutting.	Medium5	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Dual Channel VHF RadioGiven two stored frequencies, the active channel, and a target, find the fewest button presses to receive the target using direct entry, UP steps, or DOWN steps, plus channel switching.	Medium5	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
GazuaEach test case gives K; decide if K equals a sum of at least two consecutive integers in 1 to K-1, printing "Gazua" on yes and "GoHanGang" on no.	Medium5	MathNumber theory+1	No attempts yet	1s	512 MB	Judgeable
BookendFind the fewest bookends with base length L so that every book, kept in its original order, has a bookend on both sides, and no bookend bases overlap.	Medium5	Dynamic programmingGreedy	No attempts yet	1s	512 MB	Judgeable
Making a PalindromeFind the largest odd-length palindrome centered at index i, then answer each query by dropping the rest of the N cards.	Medium5	String matchingDynamic programming+1	No attempts yet	1s	512 MB	Judgeable
Meet at One Point!Given triangle side lengths and two cevian foot offsets along two sides, find the third offset using Ceva's theorem for the concurrent cevians.	Medium5	GeometryMath	No attempts yet	1s	512 MB	Judgeable
Small PenaltyPick one card from each of three players so the max minus min of the chosen numbers is as small as possible, and report that range.	Medium5	SortingTwo pointers+1	No attempts yet	1s	512 MB	Judgeable
PokegeneCount, for each query, how many string prefixes occur in exactly L of the K listed genomes.	Medium5	StringString matching+1	No attempts yet	2s	512 MB	Judgeable
Lipschitz ConstantGiven N points (x, f(x)), the Lipschitz constant is the maximum slope between adjacent points after sorting by x.	Medium5	GeometrySorting+1	No attempts yet	2s	512 MB	Judgeable
Building a FieldGiven N points on a circle with arc lengths between consecutive points, decide whether four trees are the vertices of some rectangle.	Medium5	Hash mapGeometry+2	No attempts yet	2s	512 MB	Judgeable
Cheap TripsOrder trips cannot be reordered and take no gaps; plan discounts across 120-minute windows to minimize total cost.	Medium5	Dynamic programmingGreedy	No attempts yet	2s	512 MB	Judgeable
The Erdös-Straus ConjectureFor each n, find the lexicographically smallest positive triple a ≤ b ≤ c with 4/n = 1/a + 1/b + 1/c.	Medium5	MathNumber theory+1	No attempts yet	5s	512 MB	Judgeable
Friendship FeeFind the cheapest way to become friends with everyone by paying each student a friend fee and using the friend-of-a-friend rule; output the minimum cost or "Oh no" when it exceeds k.	Medium5	Union-findGraph+1	No attempts yet	2s	512 MB	Judgeable
Edit DistanceGiven a binary string S, output a binary string T of the same length whose edit distance from S is more than half the length of S.	Medium5	StringGreedy	No attempts yet	1s	512 MB	Judgeable
Binary StringDelete the fewest bits from a binary string so the remaining subsequence keeps no leading zeros and has value at most K.	Medium5	StringGreedy+2	No attempts yet	0.5s	512 MB	Judgeable
AchievementsGiven practice days and a budget of paid days, find the longest run of consecutive days where the number of skipped days does not exceed the budget.	Medium5	Two pointersArray+1	No attempts yet	1s	512 MB	Judgeable
Hard DriveBuild a length-n bit string where fixed-zero positions stay zero, bit 1 and bit n are pinned, and the number of adjacent bit changes is exactly c.	Medium5	GreedyImplementation+1	No attempts yet	2s	512 MB	Judgeable
KleptographyRecover an autokey ciphertext's plaintext when only its last n letters are known, using the known tail to decrypt backwards through the keystream.	Medium5	ArrayImplementation+1	No attempts yet	2s	512 MB	Judgeable
Left and RightFind the lexicographically smallest permutation of 1..n whose consecutive moves match the given L/R string.	Medium5	GreedyStack+1	No attempts yet	2s	512 MB	Judgeable
Building a Symmetric StairGiven n unit cubes, build a symmetric stair (Ferrers diagram symmetric across the diagonal) using all n cubes, or report it is impossible.	Medium5	MathImplementation+2	No attempts yet	3s	512 MB	Judgeable
Email DestructionGiven n, k and k distinct shuffled email subjects of repeated 'Re: ' prefixes plus letters, decide whether exactly n emails could have existed before deletion.	Medium5	StringHash map+1	No attempts yet	3s	512 MB	Judgeable
Guest StudentGiven a weekly class schedule and k, find the shortest consecutive span of days covering exactly k class days.	Medium5	ArraySimulation+2	No attempts yet	2s	512 MB	Judgeable
JS MinificationGiven JS-like source lines and a reserved token list, rename words to a, b, ... in first-use order and print one line with the fewest spaces.	Medium5	StringSimulation+1	No attempts yet	2s	512 MB	Judgeable
Geunwoo's Diary DecoratingGiven N up to 10^9, find how many sticker packs (one of each digit 0-9) are needed so every integer from 0 to N can be written while reusing stickers between numbers.	Medium5	MathGreedy+1	No attempts yet	1s	256 MB	Judgeable
DefileGiven N honor scores, find the fewest unit decrements so that the repeated decrement process removes every member, with each step removing at least one.	Medium5	GreedySorting	No attempts yet	1.5s	512 MB	Judgeable
House NumbersGiven the first house number m, find the smallest n and the house x whose left and right neighbours' numbers sum equally.	Medium5	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable