Problems

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Total results29,461 problems

Dancing With the Googlers (Small)
Medium4
Greedy, Math
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Dancing With the Googlers (Large)
Medium4
Greedy
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Recycled Numbers (Small)
Medium4
Brute force, String
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Quake Live Team Split
Medium4
Dynamic programming, Brute force
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Bejeweled Befuddlement (Small1)
Medium4
Simulation, Brute force
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Battlefield (Small)
Medium4
Brute force, Math
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Marketplace Board (Small)
Medium4
Brute force, Probability+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Meeting Point (Small)
Medium4
Shortest path, Graph
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Antenna Repair (Small)
Medium4
Brute force, Geometry+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Snapper Chain (Large)
Medium4
Bit manipulation, Math
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Number Sets (Small)
Medium4
Union-find, Number theory
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Spinning Blade (Small)
Medium4
Brute force, Math
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Music Collection (Small1)
Medium4
String matching, Brute force
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Irregular Expressions (Small)
Medium4
Brute force, String
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Twibet (Large)
Medium4
Graph, DFS
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Grid Escape
Medium4
Graph, Simulation+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Closing the Loop (Small)
Medium4
Greedy, Sorting
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Snapper Chain
Medium4
Bit manipulation, Math
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Fair Warning (Large)
Medium4
Number theory
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Odd Man Out
Medium4
Bit manipulation, Hash map
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Wi-Fi Towers (Small)
Medium4
Graph, Brute force+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Decision Tree
Medium4
Tree, Recursion+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Multi-base happiness (small)
Medium4
Simulation, Hash map+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Alien Language (Large)
Medium4
String matching, Brute force
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Watersheds (Small)
Medium4
Graph, DFS+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Welcome to Code Jam (Small)
Medium4
Dynamic programming, String
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Painting a fence (small)
Medium4
Brute force, Intervals+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Minimum Keypresses for Text Entry
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Counting Ugly Expressions
Medium4
Brute force, Recursion+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Crop Triangles (Small)
Medium4
Combinatorics, Number theory+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Mousetrap (Small)
Medium4
Queue, Simulation+1
No attempts yet
Time limit
30s
Memory limit
512 MB
Judgeable
Minimum Scalar Product (Small)
Medium4
Sorting, Greedy+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Minimum Scalar Product (Large)
Medium4
Sorting, Greedy+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Milkshakes (Large)
Medium4
Greedy, Implementation
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Numbers (Small)
Medium4
Math, Number theory+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Train Timetable (Small)
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Train Timetable (Large)
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Sleep Disorder
Medium4
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ceiling Function
Medium4
Tree, Implementation+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
PIZZA ALVOLOC
Medium4
Geometry
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bit Friendship Index
Medium4
String, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Weekly Meeting
Medium4
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Household Ledger
Medium4
Prefix sum
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Climbing to the Information Science Building
Medium4
Prefix sum, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Infinite string
Medium4
String, String matching
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Road Network of a Perfect Binary Tree
Medium4
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
DNA Password
Medium4
Sliding window, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Enemy of My Enemy
Medium4
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Scrooge Minho
Medium4
Tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Candy
Medium4
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Liars
Medium4
Brute force, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Teleport 3
Medium4
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
A Restaurant for Bears
Medium4
Implementation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tree and paths of length two
Medium4
Tree, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
ABC
Medium4
Greedy, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
AB String
Medium4
Greedy, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Number Game
Medium4
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Wolves and Proper Words
Medium4
Stack, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Important Test
Medium4
Array, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rational Sequence
Medium4
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Partitioning a Queue
Medium4
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
North North West
Medium4
Math, String+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Idempotent Filter
Medium4
Simulation, Brute force+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Newton and the Apple
Medium4
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Disposable Cup
Medium4
Combinatorics, Math
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Do Not Touch Anything
Medium4
Math, Greedy
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Hello World!
Medium4
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Correcting Cheeseburgers
Medium4
BFS, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Celestial Map
Medium4
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Nailro Rail Pass Trip
Medium4
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Fast Exponentiation
Medium4
Math, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
I want to eat chicken
Medium4
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Random Number Check
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Honey
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Combinations
Medium4
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Harps and Tails
Medium4
Hash map, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tree
Medium4
Graph, Union-find+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ball collisions
Medium4
Probability, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Drawing Pebbles
Medium4
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Stacking Blocks
Medium4
Greedy, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roman numeral conversion
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robotopia
Medium4
Math, Brute force
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Lucky Letter
Medium4
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Prefix Array
Medium4
Sorting, String+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Q-index
Medium4
Sorting, Array
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Game Rank
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Dolphin
Medium4
Math, Binary search+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rearrange
Medium4
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Far Far Away
Medium4
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Lab Schedule
Medium4
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Oil Trails
Medium4
Graph, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rearranging a Sequence
Medium4
Linked list, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Justice Rains from Above!
Medium4
Sorting, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card String
Medium4
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Evenly Spaced Triples
Medium4
Hash map, Array
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Secret Meeting
Medium4
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Super Knight
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Battle Simulation
Medium4
Stack, String+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sticky Situation
Medium4
Sorting, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sonnets
Medium4
String, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Dancing With the Googlers (Small)Given each dancer's total of three judge scores and a budget of surprising triplets, maximize the count of dancers whose best score reaches p.	Medium4	GreedyMath	No attempts yet	5s	512 MB	Judgeable
Dancing With the Googlers (Large)Given each dancer's total of three close scores and a limit on surprising splits, count the most dancers that reach a best score of p.	Medium4	Greedy	No attempts yet	5s	512 MB	Judgeable
Recycled Numbers (Small)Count pairs (n, m) in [A, B] with equal digits where m is a rotation of n with no leading zero.	Medium4	Brute forceString	No attempts yet	5s	512 MB	Judgeable
Quake Live Team SplitSplit an even number of players with given skill levels into two equal-size teams so the team totals differ as little as possible.	Medium4	Dynamic programmingBrute force	No attempts yet	5s	512 MB	Judgeable
Bejeweled Befuddlement (Small1)Try each adjacent gem swap and report the most gems cleared by the full match and gravity cascade.	Medium4	SimulationBrute force	No attempts yet	5s	512 MB	Judgeable
Battlefield (Small)Permute your three troop types against fixed enemy counts to maximize the total pairwise battle score.	Medium4	Brute forceMath	No attempts yet	5s	512 MB	Judgeable
Marketplace Board (Small)Free dice roll uniform faces while fixed dice stay put, and each cell scores from the longest equal run through it, so average the total over all outcomes.	Medium4	Brute forceProbability+1	No attempts yet	5s	512 MB	Judgeable
Meeting Point (Small)Friends with different speeds start from given cities and must meet in one city, so minimize the worst arrival time over all cities.	Medium4	Shortest pathGraph	No attempts yet	5s	512 MB	Judgeable
Antenna Repair (Small)Arrange the K rods around a shared point with equal spacing to maximize the sum of adjacent triangle areas.	Medium4	Brute forceGeometry+1	No attempts yet	5s	512 MB	Judgeable
Snapper Chain (Large)You daisy-chain N snappers that toggle when powered and report whether the bulb at the end is lit after K snaps.	Medium4	Bit manipulationMath	No attempts yet	5s	512 MB	Judgeable
Number Sets (Small)Count how many disjoint sets remain after merging numbers in [A, B] that share a prime factor of at least P.	Medium4	Union-findNumber theory	No attempts yet	5s	512 MB	Judgeable
Spinning Blade (Small)Find the largest K by K square with its corners cut off whose center of mass is exactly at its center.	Medium4	Brute forceMath	No attempts yet	5s	512 MB	Judgeable
Music Collection (Small1)For each song, find the shortest substring that appears in that song and in no other song, breaking ties by a custom lexicographic order.	Medium4	String matchingBrute force	No attempts yet	5s	512 MB	Judgeable
Irregular Expressions (Small)Decide if any substring of each short lowercase string splits into matching outer words with two or more vowels around a middle word with at least one vowel.	Medium4	Brute forceString	No attempts yet	5s	512 MB	Judgeable
Twibet (Large)In a graph where each monk follows exactly one other, count for every starter how many monks hear the whisper passed down through followers.	Medium4	GraphDFS	No attempts yet	5s	512 MB	Judgeable
Grid EscapePoint each grid room at one door so exactly K players walk out of the grid, and print the direction grid or IMPOSSIBLE.	Medium4	GraphSimulation+1	No attempts yet	20s	1024 MB	Judgeable
Closing the Loop (Small)Pick equal numbers of red and blue segments with the largest lengths and subtract one centimeter per knot to get the longest alternating loop.	Medium4	GreedySorting	No attempts yet	5s	512 MB	Judgeable
Snapper ChainGiven N chained snappers acting as a binary counter and K snaps, decide whether the lamp on the last snapper receives power.	Medium4	Bit manipulationMath	No attempts yet	5s	512 MB	Judgeable
Fair Warning (Large)Given past event times, find the smallest wait y so all shifted times share the largest possible common divisor.	Medium4	Number theory	No attempts yet	5s	512 MB	Judgeable
Odd Man OutGiven an odd-length list where every number appears twice except one, find the number that appears once.	Medium4	Bit manipulationHash map	No attempts yet	5s	512 MB	Judgeable
Wi-Fi Towers (Small)Choose which towers to upgrade to protocol B so the total score is maximized, where upgrading a tower forces every tower in its range to be upgraded too.	Medium4	GraphBrute force+1	No attempts yet	5s	512 MB	Judgeable
Decision TreeParse a recursively defined decision tree, then for each animal walk the tree using its features and multiply node weights to get the probability.	Medium4	TreeRecursion+2	No attempts yet	5s	512 MB	Judgeable
Multi-base happiness (small)Find the smallest integer above 1 that reaches 1 under the digit-square-sum process in every base of each test case.	Medium4	SimulationHash map+1	No attempts yet	5s	512 MB	Judgeable
Alien Language (Large)Given a word list and patterns with letter-group tokens, count for each pattern how many words match it.	Medium4	String matchingBrute force	No attempts yet	5s	512 MB	Judgeable
Watersheds (Small)Given a height grid, follow each cell's outflow to its sink and label cells by shared sink, choosing basin letters to make the row-wise string smallest.	Medium4	GraphDFS+2	No attempts yet	5s	512 MB	Judgeable
Welcome to Code Jam (Small)Count how many ways the 19-character phrase "welcome to code jam" appears as a subsequence of the input line, and print the last four digits.	Medium4	Dynamic programmingString	No attempts yet	5s	512 MB	Judgeable
Painting a fence (small)From up to 10 offers, choose the fewest that cover sections 1 to 10000 using at most 3 distinct colors.	Medium4	Brute forceIntervals+1	No attempts yet	5s	512 MB	Judgeable
Minimum Keypresses for Text EntryAssign each letter to a key and a position so that total presses, the frequency times the position, is minimized.	Medium4	GreedySorting+2	No attempts yet	5s	512 MB	Judgeable
Counting Ugly ExpressionsInsert +, -, or nothing between adjacent digits of a digit string, count how many of the 3^(D-1) expressions evaluate to a number divisible by 2, 3, 5, or 7.	Medium4	Brute forceRecursion+2	No attempts yet	5s	512 MB	Judgeable
Crop Triangles (Small)Count triples of generated tree points whose coordinate sums are divisible by 3 in both axes.	Medium4	CombinatoricsNumber theory+1	No attempts yet	5s	512 MB	Judgeable
Mousetrap (Small)For each query index, report which card occupies that position in the unique deck that removes cards in order 1..K.	Medium4	QueueSimulation+1	No attempts yet	30s	512 MB	Judgeable
Minimum Scalar Product (Small)Permute two vectors to minimize their dot product and print the minimum.	Medium4	SortingGreedy+1	No attempts yet	5s	512 MB	Judgeable
Minimum Scalar Product (Large)Reorder the coordinates of two equal-length integer vectors so their scalar product is as small as possible, and report that minimum for each test case.	Medium4	SortingGreedy+2	No attempts yet	5s	512 MB	Judgeable
Milkshakes (Large)Assign each of N flavors malted or unmalted so every customer gets a liked type, using the fewest malted batches, or report IMPOSSIBLE.	Medium4	GreedyImplementation	No attempts yet	5s	512 MB	Judgeable
Numbers (Small)Given small n up to 30, print the last three digits of the integer part of (3 + sqrt(5))^n, formatted as Case #X: Y.	Medium4	MathNumber theory+1	No attempts yet	5s	512 MB	Judgeable
Train Timetable (Small)Given a day's timetable and a turnaround time, find the minimum number of trains that must start the day parked at each of the two stations.	Medium4	GreedySorting+2	No attempts yet	5s	512 MB	Judgeable
Train Timetable (Large)Given each train's departure and arrival times plus a turnaround time, find the minimum trainsets needed at stations A and B to run the timetable.	Medium4	GreedySorting+1	No attempts yet	5s	512 MB	Judgeable
Sleep DisorderConcatenate the natural numbers 1, 2, 3, ... into one digit string and return the digit at position N.	Medium4	MathImplementation	No attempts yet	1s	128 MB	Judgeable
Ceiling FunctionInsert each prototype's values into a binary search tree in order, then count how many distinct tree shapes appear across the prototypes.	Medium4	TreeImplementation+1	No attempts yet	5s	512 MB	Judgeable
PIZZA ALVOLOCGiven four points on the boundary of a convex polygon in the order picked, decide whether segments (1,2) and (3,4) split the pizza into four pieces.	Medium4	Geometry	No attempts yet	1s	128 MB	Judgeable
Bit Friendship IndexGiven two equal-length binary strings, find the minimum number of digit changes and character swaps to make them identical.	Medium4	StringGreedy+1	No attempts yet	1s	128 MB	Judgeable
Weekly MeetingFor each member's house, add the shortest distances to two fixed nodes and sum all results, counting unreachable as -1.	Medium4	Shortest pathGraph+1	No attempts yet	1s	512 MB	Judgeable
Household LedgerProcess point additions and range-sum queries on a ledger of N days.	Medium4	Prefix sum	No attempts yet	1s	512 MB	Judgeable
Climbing to the Information Science BuildingFind the crossing point k minimizing left-road distance from 1 to k plus crosswalk k plus right-road distance from k to n; output the smallest such k and the minimum distance.	Medium4	Prefix sumArray+2	No attempts yet	2s	512 MB	Judgeable
Infinite stringGiven two strings of length at most 50, decide whether each repeated infinitely produces the same infinite string.	Medium4	StringString matching	No attempts yet	2s	512 MB	Judgeable
Road Network of a Perfect Binary TreeFind the minimum number of cars whose vertex-disjoint paths cover every vertex of a perfect binary tree of height H exactly once.	Medium4	TreeDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
DNA PasswordCount the length-\|P\| substrings of a DNA string that contain at least the required number of each of A, C, G, and T.	Medium4	Sliding windowString+2	No attempts yet	2s	512 MB	Judgeable
The Enemy of My EnemyDecide whether the N people can be split into two camps so that every given hostile pair lands on opposite sides, which is exactly bipartiteness.	Medium4	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
Scrooge MinhoGiven a tree, place one fire station at the vertex minimizing the maximum distance to any other vertex, and output that distance.	Medium4	TreeGraph+2	No attempts yet	2s	512 MB	Judgeable
CandySum 2^K over all subsets of N candies with K elements, where the empty subset contributes 0, modulo 1,000,000,007.	Medium4	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
LiarsGiven a circular string of answers about whether the right neighbor is a liar, find the minimum number of liars consistent with all answers, or -1.	Medium4	Brute forceImplementation+1	No attempts yet	2s	512 MB	Judgeable
Teleport 3Find the shortest travel time on a grid where you can walk one unit per second or take any of three two-way teleports costing 10 seconds each.	Medium4	GraphShortest path+1	No attempts yet	2s	512 MB	Judgeable
A Restaurant for BearsEach arriving bear takes the smallest empty chair at or above its wanted number that is at least d away from every seated bear.	Medium4	ImplementationGreedy+1	No attempts yet	2s	512 MB	Judgeable
Tree and paths of length twoDecide whether some tree on N nodes has exactly S simple paths of length 2.	Medium4	TreeCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
ABCFind the lexicographically smallest length-N string over A, B, C that has exactly K pairs i < j with S[i] < S[j].	Medium4	GreedyCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
AB StringFind the length-N A/B string whose number of (A before B) pairs equals K, choosing the lexicographically smallest such string.	Medium4	GreedyCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Number GameFind the smallest positive N under 1e9 satisfying N mod P1 = X1, N mod P2 = X2, N mod P3 = X3, else print -1.	Medium4	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
Wolves and Proper WordsGiven a word of w, o, l, f, decide whether it is a concatenation of blocks w^n o^n l^n f^n for n >= 1.	Medium4	StackGreedy	No attempts yet	2s	512 MB	Judgeable
Important TestFor each variant, find the longest prefix solvable in t minutes given he may replace at most one task time with t0. Since order is fixed, choose the single task in that prefix whose copying saves the most time.	Medium4	ArrayPrefix sum+1	No attempts yet	2s	512 MB	Judgeable
Rational SequenceGiven p/q, find its index in the breadth-first ordering of the Calkin-Wilf tree, where each node p/q has children p/(p+q) and (p+q)/q.	Medium4	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Partitioning a QueueCount compositions of n whose parts avoid the arithmetic progression m, m+k, m+2k, with n up to 30 and up to 10000 test cases.	Medium4	Dynamic programmingCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
North North WestA direction string is built from copies of north and west; each prefix copy shifts the angle by 90/2^n, so compute the resulting angle as an integer or reduced fraction.	Medium4	MathString+2	No attempts yet	8s	512 MB	Judgeable
Idempotent FilterGiven a 128-bit lookup table describing a hexagonal cellular automaton filter, decide whether applying the filter twice always equals applying it once.	Medium4	SimulationBrute force+2	No attempts yet	8s	512 MB	Judgeable
Newton and the AppleGiven four sorted x-axis positions and a circle high above, print the index of the person the falling apple touches, or 0 for none.	Medium4	GeometryMath+1	No attempts yet	1s	32 MB	Judgeable
Disposable CupGiven A, B, and N, find every total height achievable by stacking N cups, where same-facing neighbors add A and opposite-facing ones add A+B.	Medium4	CombinatoricsMath	No attempts yet	1s	32 MB	Judgeable
Do Not Touch AnythingGiven an R by C grid and an N by N square, find the fewest squares needed to cover the whole grid, allowing overhang and overlap.	Medium4	MathGreedy	No attempts yet	1s	32 MB	Judgeable
Hello World!Assign distinct digits to the seven letters in hello + world so the sum equals N, then print the smallest hello in a column format.	Medium4	Brute forceMath+1	No attempts yet	1s	32 MB	Judgeable
Correcting CheeseburgersGiven a permutation of 1 to n, find the minimum number of four-part shuffles (c,a,d,b) needed to sort it into 1,2,...,n.	Medium4	BFSBrute force+2	No attempts yet	2s	512 MB	Judgeable
Celestial MapCount stars that, d years ago, lay in a plane through the origin and were exactly d from the origin.	Medium4	GeometryMath+1	No attempts yet	2s	512 MB	Judgeable
Nailro Rail Pass TripCompare the cheapest itinerary cost with and without a rail pass that discounts some fares, and decide if the pass is worth it.	Medium4	Shortest pathGraph	No attempts yet	1s	512 MB	Judgeable
Fast ExponentiationCompute A raised to the power X modulo 1,000,000,007, where A and X can be up to 10^18.	Medium4	MathBit manipulation+1	No attempts yet	1s	512 MB	Judgeable
I want to eat chickenEach person buys as many chickens as his money allows; compute how many more Sangeon eats than Dooyoung given coupon rules.	Medium4	MathSimulation+1	No attempts yet	1s	256 MB	Judgeable
Random Number CheckFor each of N numbers decide whether no digit repeats four times in a row and every divisor greater than 1 exceeds K.	Medium4	MathNumber theory+2	No attempts yet	1s	64 MB	Judgeable
HoneyGiven N hives with honey amounts, a pot of capacity M, and at most K trips, maximize the total honey collected.	Medium4	GreedySorting+1	No attempts yet	1s	64 MB	Judgeable
CombinationsGiven up to 1000 pairs (n, k), compute the binomial coefficient C(n, k) modulo 10^9+7 for each pair.	Medium4	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Harps and TailsFlip any subset of columns of an H/T grid; find the maximum number of rows that can be made all-H.	Medium4	Hash mapGreedy+2	No attempts yet	2s	512 MB	Judgeable
TreeGiven up to 10 graphs, decide for each whether it is a tree, allowing self-loops and duplicate edges.	Medium4	GraphUnion-find+1	No attempts yet	2s	512 MB	Judgeable
Ball collisionsGiven N balls on a line, each picking a direction at random, find the expected number of collisions within time T.	Medium4	ProbabilityBrute force+2	No attempts yet	2s	512 MB	Judgeable
Drawing PebblesGiven pebble counts per color, compute the probability that K randomly drawn distinct pebbles all share one color, printed to 10 decimals.	Medium4	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Stacking BlocksGiven a 0/1 top view plus front and side height maxima, output the tallest cube stack arrangement matching all three views, or -1.	Medium4	GreedyMatrix+1	No attempts yet	1s	128 MB	Judgeable
Roman numeral conversionFor each of T inputs, convert a Roman numeral to its value in Arabic numerals or an Arabic numeral between 1 and 3999 to its Roman form.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
RobotopiaGiven arms and legs per robot for two types and the group totals, find the unique positive counts of each type, or print ? if none or many.	Medium4	MathBrute force	No attempts yet	2s	512 MB	Judgeable
The Lucky LetterFind the smallest positive n whose remainder modulo every a from 2 to m equals a-1, that is, n ≡ -1 mod each a.	Medium4	Number theoryMath	No attempts yet	2s	512 MB	Judgeable
Prefix ArraySort all prefixes of a string lexicographically and print the end index of each prefix in that order.	Medium4	SortingString+1	No attempts yet	2s	512 MB	Judgeable
Q-indexGiven n citation counts, find the largest k such that at least k papers have k or more citations and the rest have at most k.	Medium4	SortingArray	No attempts yet	1s	512 MB	Judgeable
Game RankGiven a string of wins and losses, simulate the star-based ranking system and report the final rank or Legend.	Medium4	SimulationImplementation	No attempts yet	1s	512 MB	Judgeable
DolphinGiven a position n, print the n-th phrase in the repeating block-based dolphin sequence.	Medium4	MathBinary search+1	No attempts yet	1s	512 MB	Judgeable
RearrangeChoose an ordering of the array, subtract elements from n in that order until n drops to 0 or below, and report the smallest achievable result.	Medium4	GreedySorting	No attempts yet	1s	512 MB	Judgeable
Far Far AwayGiven a directed tree rooted at city 1 with weighted edges, find the maximum root-to-node path weight, or -1 if it stays below M.	Medium4	TreeDFS+2	No attempts yet	2s	512 MB	Judgeable
Lab SchedulePick days to experiment so no two chosen days are within two days of each other, maximizing the sum of visit probabilities.	Medium4	Dynamic programmingGreedy	No attempts yet	2s	512 MB	Judgeable
Oil TrailsGiven an undirected multigraph of oil trails, decide whether all edges can be covered by a walk that never returns to a house without visiting another one first.	Medium4	GraphImplementation	No attempts yet	2s	512 MB	Judgeable
Rearranging a SequenceGiven the sequence 1 to n, each request moves a named integer to the front while keeping the rest in order; output the final sequence.	Medium4	Linked listImplementation+1	No attempts yet	2s	512 MB	Judgeable
Justice Rains from Above!Given each robot's coordinates and missile speed, output the robot indices sorted by hit time (distance divided by speed), breaking ties by smaller index.	Medium4	SortingMath+1	No attempts yet	1s	128 MB	Judgeable
Card StringGiven uppercase letters taken left to right, each new card is placed at the front or back of the growing string; find the lexicographically smallest result.	Medium4	GreedyString+2	No attempts yet	1s	256 MB	Judgeable
Evenly Spaced TriplesGiven N distinct positions on a line, count how many triples of points have the middle point exactly halfway between the other two.	Medium4	Hash mapArray	No attempts yet	1s	256 MB	Judgeable
Secret MeetingGiven a weighted undirected graph and K friends' rooms, pick the room minimizing the sum of shortest-path distances from all friends; break ties by smallest room.	Medium4	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
Super KnightCount squares on an N by M board from which a knight with offsets (a,b) has exactly k legal moves.	Medium4	MathImplementation	No attempts yet	2s	512 MB	Judgeable
Battle SimulationRead a monster attack string and output the mech's counters, merging each earliest triple of R, B, L into one C.	Medium4	StackString+1	No attempts yet	2s	512 MB	Judgeable
Sticky SituationGiven N stick lengths, decide whether some three of them can form a triangle with positive area.	Medium4	SortingGreedy	No attempts yet	2s	512 MB	Judgeable
SonnetsFor each poem, reduce every line to the vowel sequence after its last stressed syllable and label lines by first occurrence to build a rhyme scheme.	Medium4	StringHash map+2	No attempts yet	2s	512 MB	Judgeable