Problems

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Total results29,416 problems

Edsger Dijkstra
Hard8
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Multiplying Digits
Hard8
Number theory, Dynamic programming+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Substitution Cipher Key
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
King
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Romeo and Juliet
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Minimum Chain Cover
Hard8
Graph, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Distance to the nearest point
Hard8
Geometry, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Farthest White Pair in a Tree
Hard8
Tree, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Vertices connected by the same color
Hard8
Tree, Union-find+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
K-th smallest weight on a tree path
Hard8
Tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Jack and the Beanbag
Hard8
Game theory, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Compensation
Hard8
Binary search, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence and Queries 1
Hard8
Segment tree, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Palindromes and Queries
Hard8
Segment tree, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Buying Stamps
Hard8
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Weighted sum queries on a mutable sequence
Hard8
Tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence and Queries 3
Hard8
Segment tree, Binary search+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Sequence and Queries 7
Hard8
Prefix sum, Divide and conquer+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Counting close pairs in a range
Hard8
Divide and conquer, Prefix sum+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Sequence and Queries 10
Hard8
Segment tree, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bridge Park
Hard8
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Independent Edge Set and Certificate
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Memory Cell
Hard8
Stack, Tree+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Room
Hard8
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Feasible rounding
Hard8
Greedy, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Virus
Hard8
Tree, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Knight Moves 2
Hard8
Matrix, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence Transformation
Hard8
Combinatorics, Bit manipulation+2
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Hot Potato
Hard8
Graph, Probability+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Olympic Gold Athletes
Hard8
Geometry, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rectangular Plaza
Hard8
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Ominobox
Hard8
Brute force, Implementation+2
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Dona Minhoca
Hard8
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ecology Preserve
Hard8
Dynamic programming, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Olympics
Hard8
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Balloon
Hard8
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tire Patches
Hard8
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Marble slide
Hard8
Geometry, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Integral
Hard8
Intervals
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Street Detour
Hard8
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
War Among the Stars
Hard8
Geometry, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Largest Increasing Submatrix
Hard8
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Scientists' Regatta
Hard8
Geometry, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence and Queries 11
Hard8
Prefix sum, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
XOR Sum 2
Hard8
Bit manipulation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Kirchhoff's Laws
Hard8
Graph, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Number of Divisors
Hard8
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
It looks like the Fibonacci sequence, but...
Hard8
Math, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Burza
Hard8
Game theory, Tree+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Factorial Fraction Equation
Hard8
Number theory, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Linear Recurrence RNG
Hard8
Math, Divide and conquer+1
No attempts yet
Time limit
15s
Memory limit
512 MB
Judgeable
Five-Dimensional Chocolate
Hard8
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Determinants and GCD
Hard8
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Last 13 digits of a Fibonacci number
Hard8
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Number of good trees
Hard8
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ghostbusters 2
Hard8
Geometry, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Base Sums
Hard8
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Enclosure
Hard8
Geometry, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Maximum Tent Volume
Hard8
Geometry, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Calculating Taxes
Hard8
Dynamic programming, Tree+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Hiking
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Individually Customised Pop-up Cards
Hard8
Geometry, Math+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Krypton Stadiums
Hard8
Intervals, Greedy+2
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
What Next
Hard8
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rtetris
Hard8
Dynamic programming, Simulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Revenge of the Champernowne Constant
Hard8
String, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Subsets whose lexicographic order matches
Hard8
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Sky Jump
Hard8
Math, Geometry+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Dice Room
Hard8
BFS, Simulation+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Alice and the Bomb
Hard8
Geometry, Shortest path+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Camera Control
Hard8
Geometry, Dynamic programming+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Water Tank
Hard8
Binary search, Simulation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Neko's Treasure
Hard8
Geometry, BFS+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Dig or Climb
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Rotation Estimation
Hard8
Geometry, Sorting+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Controlled Tournament
Hard8
Divide and conquer, Dynamic programming+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Ramen Shop Seating
Hard8
Simulation, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Cousin's Aunt
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Colony Maintenance
Hard8
Graph, BFS+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Disarmament of the Units
Hard8
BFS, Graph+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Turn Polygons
Hard8
Geometry, Binary search+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Online Quiz System
Hard8
Simulation, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Palindrome cipher decryption
Hard8
Dynamic programming, String+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Traffic Signals
Hard8
Shortest path, Graph+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Restriction Enzyme Map
Hard8
Brute force, Backtracking+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
The Extreme Slalom
Hard8
Geometry, Dynamic programming+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Eight Princes
Hard8
Combinatorics, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Light the Room
Hard8
Geometry, Simulation
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Three Squares
Hard8
Binary search, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Favorite music
Hard8
String matching, Trie+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Exam
Hard8
Dynamic programming, String matching+2
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Back to the Future
Hard8
Graph, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Counting Self-Rotating Subsets
Hard8
Geometry, Combinatorics
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Emission Spectrum
Hard8
Binary search, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Game of Matchings
Hard8
String matching, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Internet Trouble
Hard8
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Washroom Satisfaction Index
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Find C
Hard8
Number theory, Geometry+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
ACM Tax
Hard8
Tree, Binary search+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Dictionary Game
Hard8
Game theory, Trie+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Edsger DijkstraGiven a program of labeled print statements and if-goto statements with counters that are true for a bounded number of times, decide whether transforming every if-goto into a do-while loop keeps the program's output and compiles.	Hard8	SimulationImplementation+2	No attempts yet	2s	256 MB	Judgeable
Multiplying DigitsGiven base B and target N, find the smallest positive integer whose base-B digits multiply to N, or report that none exists.	Hard8	Number theoryDynamic programming+2	No attempts yet	3s	512 MB	Judgeable
Substitution Cipher KeyGiven N distinct words and a target permutation, find the lexicographically smallest substitution cipher key that sorts the encrypted words into that order, or report none.	Hard8	GreedySorting+2	No attempts yet	1s	64 MB	Judgeable
KingN elves each target a dwarf; elves enter one at a time and slide clockwise to the next free spot. Choose the entry order to maximize elven wins.	Hard8	GreedySorting+2	No attempts yet	2s	128 MB	Judgeable
Romeo and JulietCompute each person's maximum guilt-to-Juliet and pain-to-Romeo transfer product, weight every event, then remove up to k events to minimize the total.	Hard8	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
Minimum Chain CoverGiven a DAG, find the minimum number of vertex-disjoint directed paths that together cover every vertex.	Hard8	GraphDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Distance to the nearest pointFor each of N points, report the Manhattan distance to the nearest other point.	Hard8	GeometryDivide and conquer+1	No attempts yet	2s	512 MB	Judgeable
Farthest White Pair in a TreeMaintain a tree whose vertices flip between white and black, and after each flip report the largest distance between two white vertices, where edge lengths may be negative.	Hard8	TreeDivide and conquer+2	No attempts yet	2s	512 MB	Judgeable
Vertices connected by the same colorProcess color flip and reachability queries on a tree where two vertices are connected if every vertex on their path has the same color.	Hard8	TreeUnion-find+2	No attempts yet	2s	512 MB	Judgeable
K-th smallest weight on a tree pathFor each query, print the k-th smallest vertex weight on the unique tree path between two vertices.	Hard8	TreeBinary search+2	No attempts yet	2s	512 MB	Judgeable
Jack and the BeanbagFind the minimum number of cows Jack needs so that, against adversarial farms, he secures the required count of each bean kind.	Hard8	Game theoryDynamic programming+1	No attempts yet	3s	512 MB	Judgeable
CompensationGiven scheduled trains with known delays, find the smallest start time of a booking whose promised arrival is at least 1800 seconds before any possible real arrival at station N.	Hard8	Binary searchDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Sequence and Queries 1Given a static sequence, answer M queries counting how many values in range A[i..j] are greater than k.	Hard8	Segment treeSorting+2	No attempts yet	1s	512 MB	Judgeable
Palindromes and QueriesSupport range character assignments and count palindromic substrings of length at most K inside a queried range.	Hard8	Segment treeString+2	No attempts yet	2s	512 MB	Judgeable
Buying StampsCount the ways to spend exactly K won using N kinds of 1-won stamps and M kinds of 2-won stamps, allowing repeats, modulo prime P.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Weighted sum queries on a mutable sequenceMaintain a sequence under insert, delete, and replace, and answer weighted-sum range queries where each element is multiplied by its offset to the power k (k up to 10).	Hard8	TreeBinary search+2	No attempts yet	2s	512 MB	Judgeable
Sequence and Queries 3Given a static sequence, answer queries (decoded with the previous answer via XOR) counting how many elements in a subarray exceed k.	Hard8	Segment treeBinary search+1	No attempts yet	1s	512 MB	Judgeable
Sequence and Queries 7For each query range, find the longest subarray whose sum is divisible by K.	Hard8	Prefix sumDivide and conquer+1	No attempts yet	4s	512 MB	Judgeable
Counting close pairs in a rangeGiven a sequence and K, each query asks how many index pairs inside a subarray have value difference at most K.	Hard8	Divide and conquerPrefix sum+2	No attempts yet	3s	512 MB	Judgeable
Sequence and Queries 10For each query with ranges [x1,y1] and [x2,y2], find the maximum subarray sum A_i+...+A_j where i is in the first range and j is in the second.	Hard8	Segment treePrefix sum+1	No attempts yet	2s	512 MB	Judgeable
Bridge ParkGiven a connected planar straight-line graph on convex-position vertices, add the fewest non-crossing edges so the graph becomes 2-edge-connected.	Hard8	GraphGreedy+1	No attempts yet	1s	512 MB	Judgeable
Independent Edge Set and CertificateFind a maximum matching and a maximum independent vertex set in a bipartite graph, printing both with lexicographically smallest tie-breaks.	Hard8	GraphShortest path+2	No attempts yet	1s	512 MB	Judgeable
Memory CellBuild the expression tree, find the largest pair of disjoint identical subtrees, and print the loser's postfix in lexicographic order.	Hard8	StackTree+2	No attempts yet	1s	512 MB	Judgeable
RoomGiven points on the edges of an unknown orthogonal monotone polygon with edge orientations, reconstruct it and output its perimeter or -1 if impossible.	Hard8	GeometrySorting+2	No attempts yet	2s	512 MB	Judgeable
Feasible roundingRound each decimal entry to floor or ceiling so that every row and column sum still matches its stated total, choosing the lexicographically smallest whole table.	Hard8	GreedyMatrix+2	No attempts yet	1s	512 MB	Judgeable
VirusGiven a binary tree, find the minimum number of nodes that end up infected when one node may be protected each round.	Hard8	TreeDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Knight Moves 2Count knight paths of length at most k on a 2n by 2n board that start at the top-left corner and end on any corner, modulo 1000007.	Hard8	MatrixDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Sequence TransformationCount length-n integer sequences with entries in [1, 2^k) whose prefix bitwise-OR values are strictly increasing, for n up to 1e18 and k up to 30000.	Hard8	CombinatoricsBit manipulation+2	No attempts yet	10s	512 MB	Judgeable
Hot PotatoFor each query range, find the smallest X maximizing the gap between ending and not ending, given a functional graph walk from a uniform random start.	Hard8	GraphProbability+2	No attempts yet	2s	512 MB	Judgeable
Olympic Gold AthletesEach athlete's skill and fatigue change linearly in time; count those who are the unique max-skill and unique min-fatigue athlete at some time t >= 0.	Hard8	GeometryBinary search+2	No attempts yet	1s	512 MB	Judgeable
Rectangular PlazaCount axis-aligned rectangles whose corners include two given lamps and whose interior contains no other lamp, given all X and Y coordinates are distinct.	Hard8	GeometrySorting+1	No attempts yet	1s	512 MB	Judgeable
OminoboxFor every fixed N-omino placement in a small grid, the drop score is H minus the maximum stack height covered; sum the best placement score over all N-ominoes.	Hard8	Brute forceImplementation+2	No attempts yet	10s	512 MB	Judgeable
Dona MinhocaOn a cactus graph, for each query (entry chamber, worm length) decide whether a closed non-backtracking walk of length at most M exists and give the shortest such distance.	Hard8	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Ecology PreserveGiven an N by N grid of tree counts, pick a connected set of exactly M cells (M at most 10) maximizing the total tree count.	Hard8	Dynamic programmingDFS+2	No attempts yet	2s	512 MB	Judgeable
OlympicsGiven daily flight capacities, find the minimum number of days for all athletes to travel from airport 1 to airport N.	Hard8	GraphBFS+1	No attempts yet	1s	512 MB	Judgeable
BalloonGiven N disjoint ceiling segments, trace each vertically rising balloon as it sticks to horizontal segments or slides to the higher endpoint of tilted ones, and report the final resting point or escape x coordinate.	Hard8	GeometrySorting+2	No attempts yet	2s	512 MB	Judgeable
Tire PatchesOn a circular tire, cover all hole positions with the minimum total length of uncut patches of two given lengths and return that total length.	Hard8	Dynamic programmingArray+2	No attempts yet	2s	512 MB	Judgeable
Marble slideA ball rolls down alternating left and right fins, and we must find the largest diameter for which it still slides all the way to the bottom instead of getting wedged.	Hard8	GeometryBinary search+2	No attempts yet	2s	512 MB	Judgeable
IntegralGiven f at a set of integer points, extend it to a monotone piecewise linear function so the integral from 0 to n equals y.	Hard8	Intervals	No attempts yet	2s	512 MB	Judgeable
Street DetourFor each test, after removing street 1, decide whether the graph stays strongly connected, or becomes so by reversing one-way streets or by making streets two-way.	Hard8	GraphBFS+1	No attempts yet	2s	512 MB	Judgeable
War Among the StarsCompute the shortest distance between two tetrahedra in space, given the coordinates of their eight vertices.	Hard8	GeometryImplementation+1	No attempts yet	2s	512 MB	Judgeable
Largest Increasing SubmatrixGiven a matrix, find the largest rectangular submatrix whose row-by-row linearization is strictly increasing.	Hard8	Dynamic programmingMatrix+1	No attempts yet	2s	512 MB	Judgeable
Scientists' RegattaGiven start, finish, and non-intersecting segment obstacles in the plane, compute the shortest path that never crosses a segment interior.	Hard8	GeometryShortest path+2	No attempts yet	2s	512 MB	Judgeable
Sequence and Queries 11Given an array and integer K, answer queries counting subarrays within [l, r] whose XOR equals K.	Hard8	Prefix sumHash map+2	No attempts yet	2s	512 MB	Judgeable
XOR Sum 2Pick any subsequence of up to 100,000 numbers under 10^18 so that the XOR of the chosen elements is maximum.	Hard8	Bit manipulationGreedy+1	No attempts yet	2s	512 MB	Judgeable
Kirchhoff's LawsGiven a resistor network, compute the equivalent resistance between node 1 and node N by solving Kirchhoff's laws.	Hard8	GraphMath+2	No attempts yet	2s	512 MB	Judgeable
Number of DivisorsGiven a, b, c up to 2000, compute the sum over all i<=a, j<=b, k<=c of the divisor count of ijk, modulo 2^30.	Hard8	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
It looks like the Fibonacci sequence, but...Sum F_i times i^k for i from 1 to n, where F is Fibonacci with F_1=1, F_2=2, and n can reach 10^17.	Hard8	MathDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
BurzaGiven a tree and a blind pre-committed node-marking order, decide whether the coin can be forced to move fewer than K times regardless of the adversary's play.	Hard8	Game theoryTree+2	No attempts yet	1s	512 MB	Judgeable
Factorial Fraction EquationCount ordered pairs of positive integers (X, Y) satisfying 1/N! = 1/X + 1/Y, printing the exact value with no modulus.	Hard8	Number theoryCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
Linear Recurrence RNGGiven the first k terms and coefficients of a linear recurrence and a huge index N, compute the N-th term modulo 104857601.	Hard8	MathDivide and conquer+1	No attempts yet	15s	512 MB	Judgeable
Five-Dimensional ChocolateCount the ways to tile a 2x2x2x2xn five-dimensional box with 1x1x1x1x2 domino pieces, modulo 1000000007.	Hard8	Dynamic programmingMath+1	No attempts yet	2s	512 MB	Judgeable
Determinants and GCDFor a tridiagonal matrix with a fixed pattern, let D(k) be its k-by-k determinant and compute the sum of gcd(D(i), D(N)) for i from 1 to N, modulo 1e9+7.	Hard8	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Last 13 digits of a Fibonacci numberGiven n between 1 and 10^13, find the smallest index i such that the last 13 digits of the i-th Fibonacci number equal n, or print -1.	Hard8	MathNumber theory+1	No attempts yet	2s	512 MB	Judgeable
Number of good treesCount labeled trees on kn nodes split into n blocks of size k, with no edge inside a block, modulo 1e9+7.	Hard8	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Ghostbusters 2Assign each of N points a horizontal or vertical cross arm of equal length P so no two same-orientation arms intersect; find the max P or report UNLIMITED.	Hard8	GeometryBinary search+2	No attempts yet	2s	512 MB	Judgeable
Base SumsGiven n, a, b, find the smallest m greater than n whose digit sum in base a equals its digit sum in base b.	Hard8	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
EnclosureGiven k controlled points forming a convex hull, add one of the remaining points to maximize the hull area, and print the resulting area to one decimal.	Hard8	GeometryGreedy+2	No attempts yet	2s	512 MB	Judgeable
Maximum Tent VolumeAssign n poles of given heights to a central hole and n-1 fixed holes around it to maximize the total volume of the resulting triangles.	Hard8	GeometryDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Calculating TaxesOn a tree where each house picks a divisor of its income, maximize the total sum of chosen values so that every pair of adjacent houses picks coprime values.	Hard8	Dynamic programmingTree+2	No attempts yet	8s	512 MB	Judgeable
HikingGiven directed step costs on a grid with no negative cycles, find the average shortest path over all ordered pairs of distinct cells, rounded up.	Hard8	GraphShortest path+2	No attempts yet	10s	512 MB	Judgeable
Individually Customised Pop-up CardsFor a pop-up card folding on parallel axes, find the minimum distance to move the contact point (Xp,0) so a matching second segment exists.	Hard8	GeometryMath+2	No attempts yet	3s	512 MB	Judgeable
Krypton StadiumsGiven n intervals where interval i contains point i, classify the layout as Great, Acceptable, or Bad based on whether pairs of cities are co-hosted by a nesting or shared stadium.	Hard8	IntervalsGreedy+2	No attempts yet	10s	512 MB	Judgeable
What NextGiven a prefix of an NZPC Speak program cut at an arbitrary point, list the symbols that can legally come next, respecting declarations, masking, and partial names.	Hard8	ImplementationSimulation+2	No attempts yet	2s	512 MB	Judgeable
RtetrisGiven a fixed 6 by 7 pit and a hand of up to 200 Tetris pieces, decide if all pieces can be placed without creating a gap, and maximize cleared rows.	Hard8	Dynamic programmingSimulation+1	No attempts yet	2s	512 MB	Judgeable
Revenge of the Champernowne ConstantGiven a digit string S of length up to 100, find the 1-indexed position of its first occurrence in the Champernowne constant 0.123456789101112...	Hard8	StringMath+2	No attempts yet	8s	512 MB	Judgeable
Subsets whose lexicographic order matchesCount non-empty subsets of the integers from A to B whose numeric order equals their lexicographic decimal order, modulo P.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Sky JumpGiven N engines that instantly set velocity, each usable once, decide if the gravity-driven missile starting at the origin can pass through a target point.	Hard8	MathGeometry+2	No attempts yet	8s	512 MB	Judgeable
Dice RoomGiven hole patterns on the six faces of a cube, find the fewest 90-degree rolls so that holes exist at the right positions on the front and back faces.	Hard8	BFSSimulation+1	No attempts yet	8s	512 MB	Judgeable
Alice and the BombGiven disjoint polygons, a bomb point, and Alice at the origin, find the shortest path she runs outside all polygon interiors until some building blocks the blast to the bomb.	Hard8	GeometryShortest path+2	No attempts yet	8s	512 MB	Judgeable
Camera ControlMembers move along timed polygonal routes around a fixed camera, and you may switch followers only when two members lie on the same ray; maximize total time filming a singing member.	Hard8	GeometryDynamic programming+1	No attempts yet	8s	512 MB	Judgeable
Water TankGiven a daily repeating schedule of water usage, find the minimum constant pump rate that keeps the tank from ever running dry.	Hard8	Binary searchSimulation+2	No attempts yet	8s	512 MB	Judgeable
Neko's TreasureGiven n disjoint-or-nested circles, choose a valid subset so the rat crossing from its lair to the bed crosses the fewest walls.	Hard8	GeometryBFS+1	No attempts yet	8s	512 MB	Judgeable
Dig or ClimbGiven a polyline terrain cross-section, find the shortest travel time from the first point to the last, walking along the surface or tunneling horizontally between two same-height points whose interior stays below the terrain.	Hard8	GraphShortest path+2	No attempts yet	8s	512 MB	Judgeable
Rotation EstimationGiven two unordered point sets related by a rotation plus translation, find the smallest counterclockwise rotation angle in [0, 2pi) that maps the first set onto the second.	Hard8	GeometrySorting+2	No attempts yet	8s	512 MB	Judgeable
Controlled TournamentCount knockout brackets of minimum height in which player M wins the tournament, given a fixed win relation over N up to 16 players.	Hard8	Divide and conquerDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Ramen Shop SeatingSimulate a ramen shop with N counters of fixed seats where arriving groups pick the best free block under a preference rule and may leave if they wait too long; report average customer satisfaction.	Hard8	SimulationImplementation+2	No attempts yet	8s	512 MB	Judgeable
Cousin's AuntGiven a chain of up to ten kinship terms describing how C relates to A, report the maximum and minimum possible degree of kinship between A and C.	Hard8	GraphShortest path+2	No attempts yet	8s	512 MB	Judgeable
Colony MaintenanceGiven up to 16 unit cubes forming a connected polycube, find the shortest path over its exposed surface between two points, with moves constrained by the three surface-adjacency cases.	Hard8	GraphBFS+2	No attempts yet	8s	512 MB	Judgeable
Disarmament of the UnitsFind the minimum number of alternating single-unit moves so that every ACM and ICPC unit reaches its designated disarmament town without violating occupancy or same-road rules.	Hard8	BFSGraph+2	No attempts yet	8s	512 MB	Judgeable
Turn PolygonsGiven a rotating polygon around a center and a fixed convex polygon inside it, find the angle until the two polygons first touch.	Hard8	GeometryBinary search+2	No attempts yet	8s	512 MB	Judgeable
Online Quiz SystemGiven per-player delays and each player's answer timing, simulate the polling protocol and report bytes sent and received by the server and each player.	Hard8	SimulationImplementation+2	No attempts yet	8s	512 MB	Judgeable
Palindrome cipher decryptionFor each string, find its longest palindromic subsequence and output the lexicographically smallest one among those of maximal length.	Hard8	Dynamic programmingString+2	No attempts yet	8s	512 MB	Judgeable
Traffic SignalsOn a grid of streets with individually timed traffic lights, find the driving time of the fastest route from home to a friend's house, waiting at red lights.	Hard8	Shortest pathGraph+1	No attempts yet	8s	512 MB	Judgeable
Restriction Enzyme MapReconstruct which positions on a circular DNA of length up to 20 are cut by enzyme A or B, given the distinct fragment lengths from cutting with A, with B, and with both, minimizing site count then lexicographic order.	Hard8	Brute forceBacktracking+2	No attempts yet	8s	512 MB	Judgeable
The Extreme SlalomGiven up to 12 disjoint line-segment gates in order, find the shortest path that touches each gate in sequence.	Hard8	GeometryDynamic programming+1	No attempts yet	8s	512 MB	Judgeable
Eight PrincesCount the ways to seat eight distinct princes on N round-table seats so that no two occupy adjacent seats or opposite seats (opposite only when N is even).	Hard8	CombinatoricsMath+2	No attempts yet	8s	512 MB	Judgeable
Light the RoomGiven an orthogonal polygon room with a lamp, trace rays that reflect once off the walls and find the total wall length left unlit.	Hard8	GeometrySimulation	No attempts yet	8s	512 MB	Judgeable
Three SquaresGiven N integer points, find the smallest side length L so that three equal axis-parallel squares of side L can cover every point.	Hard8	Binary searchSorting+2	No attempts yet	1s	256 MB	Judgeable
Favorite musicGiven n note strings and q pairs, find the shortest string containing both given fragments as contiguous substrings, allowing overlap.	Hard8	String matchingTrie+2	No attempts yet	1s	256 MB	Judgeable
ExamGiven each student's fixed semester points and a distribution of exam points, find the probability that the grade string avoids all forbidden substrings.	Hard8	Dynamic programmingString matching+2	No attempts yet	1.5s	512 MB	Judgeable
Back to the FutureGiven a graph of compatible pairs, find the largest vertex subset where each chosen vertex has at least A neighbors and at least B non-neighbors inside the subset.	Hard8	GraphGreedy+2	No attempts yet	2s	512 MB	Judgeable
Counting Self-Rotating SubsetsFor each size i, count the subsets of the given N points that a nontrivial rotation maps onto themselves, modulo 1e9+7.	Hard8	GeometryCombinatorics	No attempts yet	2s	512 MB	Judgeable
Emission SpectrumMaintain an integer array under adjacent swaps and answer k-th smallest value queries over subarrays online.	Hard8	Binary searchDivide and conquer+2	No attempts yet	2s	512 MB	Judgeable
Game of MatchingsCount substrings of S that match pattern P under a bijective letter-to-number mapping, where distinct numbers must get distinct letters.	Hard8	String matchingString+2	No attempts yet	2s	512 MB	Judgeable
Internet TroublePlace 1 to N stations on a line of towns to minimize station cost plus weighted cable cost, where each house connects to the nearest station.	Hard8	Dynamic programmingDivide and conquer+2	No attempts yet	2s	512 MB	Judgeable
Washroom Satisfaction IndexAfter each point update to guest washroom times, compute the minimum sum over assignments of wait-plus-service times to W washrooms, where each washroom serves a subset in some order.	Hard8	GreedySorting+2	No attempts yet	10s	512 MB	Judgeable
Find CGiven lattice points A and B, list K lattice points C such that both segments AC and BC are primitive and triangle ABC contains no other lattice point.	Hard8	Number theoryGeometry+2	No attempts yet	1s	512 MB	Judgeable
ACM TaxFor each query path in a weighted tree, output the median edge length, rounded to one decimal.	Hard8	TreeBinary search+2	No attempts yet	5s	512 MB	Judgeable
Dictionary GameWords are destroyed by prefix cuts; after each insertion into the dictionary, report which player wins the impartial game under optimal play.	Hard8	Game theoryTrie+2	No attempts yet	5s	512 MB	Judgeable