Interview core

Mediums from real onsites

Under construction

Still being built. Things may change

Total results3,617 problems

Production System Management
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Inspection
Medium5
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chairs
Medium5
Sorting, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Writing the Score
Medium5
Dynamic programming, Sliding window
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Easy Assembly
Medium5
Hash map, Implementation+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Circular Circus
Medium5
Implementation, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lethargic Lumen
Medium5
Graph, Tree+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fujiyama Thursday
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jumping Frog
Medium5
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Knights Airways
Medium5
Topological sort, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Spaces, the Final Frontier
Medium5
Dynamic programming, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Adrian
Medium5
Prefix sum, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chocolates
Medium5
Greedy, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Prijateljice
Medium5
Game theory, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Image Labeler
Medium5
Sorting, Greedy+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Maximum Gain
Medium5
Array, Prefix sum
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable
Touchbar Typing
Medium5
Dynamic programming, Array
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Happy Subarrays
Medium5
Prefix sum, Array+1
No attempts yet
Time limit
25s
Memory limit
1024 MB
Judgeable
Running in Circles
Medium5
Simulation, Math
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Electricity
Medium5
Tree, Dynamic programming+1
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Board Arrangements for Concentration Games
Medium5
Backtracking, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pizza delivery
Medium5
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
#include
Medium5
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
(N+1)-legged race
Medium5
Sorting, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
SubsetCheating
Medium5
Math, Combinatorics
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
NiceSet
Medium5
Sorting, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Square Pen
Medium5
Matrix, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Semiperfect
Medium5
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Repeat
Medium5
String, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
God of Battle
Medium5
Greedy, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
map, filter
Medium5
Array, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Find the permutation
Medium5
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shiroko and the Bank Robbery
Medium5
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Polish Language
Medium5
String, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
New Contract
Medium5
Greedy, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gramfan
Medium5
Two pointers, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Diagnostic 0 : 1
Medium5
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Power Plants and Factories
Medium5
Prefix sum, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Delivery Vans
Medium5
Hash map, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Oranżada
Medium5
Greedy, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ornitolog 2
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Agar.io
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Lollipop
Medium5
Sliding window, Hash map
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Smallest Sum
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
High-Heeled Flip-Flops
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Antipalindrome
Medium5
String, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fine Optimization
Medium5
Greedy, Sorting
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Alternating Word II
Medium5
Dynamic programming, String
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Strong Numbers
Medium5
Bit manipulation, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pool
Medium5
Greedy, Implementation
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
The Boards Strike Back
Medium5
Binary search, Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Minusy
Medium5
String, Two pointers+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Unlucky Numbers
Medium5
Dynamic programming, String
No attempts yet
Time limit
12s
Memory limit
1024 MB
Judgeable
Zigzag
Medium5
Simulation, Math
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Video Editor
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Sum of Primes
Medium5
Two pointers, Sliding window+1
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Szarlotka
Medium5
Prefix sum, Binary search
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Crossword
Medium5
Hash map, String matching+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Wyliczanka
Medium5
Array, Simulation+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Making It Smaller
Medium5
Greedy, String+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Metro Plan
Medium5
Sorting, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lawyers
Medium5
Intervals, Heap+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
XOR Pairs
Medium5
Bit manipulation, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Not One
Medium5
Tree, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Maxdifficent Group
Medium5
Prefix sum, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bricks in the Wall
Medium5
Matrix, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Skridskor
Medium5
BFS, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Portals
Medium5
Graph, Tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Expression
Medium5
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cave Escape
Medium5
BFS, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dance Mat
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fotografen
Medium5
Greedy, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Nice Numbers
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Orienteering
Medium5
Graph, BFS+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Sock Matching 2
Medium5
Sorting, Binary search+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
The board game
Medium5
Game theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Springoalla
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Summa Summarum
Medium5
Binary search, Sorting
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Bookshelves
Medium5
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tivoli
Medium5
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ant Colony
Medium5
Prefix sum, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Feeding the Cows
Medium5
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Treats for the Cows
Medium5
Dynamic programming, Two pointers
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stall Reservations
Medium5
Greedy, Heap+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Redundant Paths
Medium5
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Corral the Cows
Medium5
Binary search, Prefix sum
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Grove
Medium5
BFS, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Knights of Ni
Medium5
BFS, Matrix+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Scales
Medium5
Greedy, Backtracking
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Skiing
Medium5
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Yogurt factory
Medium5
Greedy, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cube Stacking
Medium5
Union-find, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Turning in Homework
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Paranoid Cows
Medium5
Sorting, Binary search
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Breeding
Medium5
Dynamic programming, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pesky Parentheses
Medium5
Greedy, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cow Exhibition
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Milking Grid
Medium5
String, String matching+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Popular Cows
Medium5
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Beauty Contest
Medium5
Geometry, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Production System ManagementGiven N jobs whose success probability rises with each extra machine, buy machines within budget B to maximize the product of all success probabilities.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	512 MB	Judgeable
InspectionFind the fewest new one-way roads to add so that the towns contain a round trip (directed cycle), or report -1 if impossible.	Medium5	Shortest pathGraph+1	No attempts yet	1s	1024 MB	Judgeable
ChairsFind the lexicographically smallest shortest R/D path from the top-left to the bottom-right cell that visits every chair, or report Impossible.	Medium5	SortingDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Writing the ScoreGiven a sequence of notes and rests, find the fewest pages of at most X symbols where each page except the last ends with K consecutive rests.	Medium5	Dynamic programmingSliding window	No attempts yet	1s	1024 MB	Judgeable
Easy AssemblyGiven towers of distinct numbers, find the fewest split and combine operations needed to stack all blocks into one tower sorted ascending from the top.	Medium5	Hash mapImplementation+1	No attempts yet	3s	1024 MB	Judgeable
Circular CircusFrom each rotation's count of northernmost changes and the final northernmost letter, rebuild the circular seating order or report inconsistency.	Medium5	ImplementationArray+1	No attempts yet	1s	1024 MB	Judgeable
Lethargic LumenGiven an acyclic undirected graph with n nodes, add edges to make it a tree and print the smallest possible diameter.	Medium5	GraphTree+2	No attempts yet	1s	1024 MB	Judgeable
Fujiyama ThursdayAssign four diners to each car, given arrival times and eating speeds, so that the last person finishes eating as early as possible.	Medium5	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Jumping FrogGiven a start point and a target point, decide whether repeated jumps of the form (x+y, y), (x-y, y), (x, y+x), or (x, y-x) can connect them.	Medium5	Number theoryMath	No attempts yet	1s	1024 MB	Judgeable
Knights AirwaysGiven flight schedules, order the flights so each arrival into a city comes before departures from that city, picking the smallest flight numbers first.	Medium5	Topological sortGraph+1	No attempts yet	1s	1024 MB	Judgeable
Spaces, the Final FrontierSplit a string with no spaces into dictionary words so the sum of their values is maximized, breaking ties by the earliest space.	Medium5	Dynamic programmingHash map+1	No attempts yet	1s	1024 MB	Judgeable
AdrianCount the substrings of a lowercase word whose letters can be rearranged into a palindrome.	Medium5	Prefix sumBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
ChocolatesFor each query, pick m chocolates to minimize Lana's payment minus Fran's payment, where Fran pays only the part of each price above k.	Medium5	GreedyPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
PrijateljiceTwo players alternately say larger words from their own sorted lists, starting with the same or next letter. Decide the winner if Leona opens with her smallest word.	Medium5	Game theoryDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Image LabelerSplit N regions into M non-empty categories to maximize the sum of each category's median participant count.	Medium5	SortingGreedy+1	No attempts yet	Not set	1024 MB	Judgeable
Maximum GainGiven two arrays and K, take K points total by removing elements from either end of each array to maximize the sum.	Medium5	ArrayPrefix sum	No attempts yet	30s	1024 MB	Judgeable
Touchbar TypingGiven a word S and a one-row keyboard K, find the minimum finger movement time to type every character of S in order.	Medium5	Dynamic programmingArray	No attempts yet	Not set	1024 MB	Judgeable
Happy SubarraysGiven an array A, find the sum of the values of all subarrays whose every prefix sum is non-negative.	Medium5	Prefix sumArray+1	No attempts yet	25s	1024 MB	Judgeable
Running in CirclesGiven a circular track of length L and a series of runs with distances and directions, count the laps the machine records for Ada.	Medium5	SimulationMath	No attempts yet	Not set	1024 MB	Judgeable
ElectricityGiven a tree where power flows only to neighbors with strictly lower capacity, find the most junctions one powered junction can reach.	Medium5	TreeDynamic programming+1	No attempts yet	40s	1024 MB	Judgeable
Board Arrangements for Concentration GamesCount the perfect pairings of a 4x4 grid where each pair of cells differs by one of four given offsets, treating swapped labelings as the same pattern.	Medium5	BacktrackingBrute force	No attempts yet	1s	1024 MB	Judgeable
Pizza deliveryGiven N customers with delivery times t_i and irritability a_i, find the single-courier delivery order that minimizes total stress.	Medium5	GreedySorting	No attempts yet	2s	1024 MB	Judgeable
#includeGiven a directed include graph, find the smallest set of files whose direct inclusion covers all files, breaking ties by the smallest sum of file numbers.	Medium5	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
(N+1)-legged racePick N students and an order so that the sum of their abilities minus the total height gaps between neighbors is as large as possible.	Medium5	SortingDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
SubsetCheatingCount the score assignments over N problems where Little Triangle's score is at most Little Square's on each problem, with totals A and B, modulo 1e9+7.	Medium5	MathCombinatorics	No attempts yet	1s	1024 MB	Judgeable
NiceSetGiven n integers and a bound S, find the size of the largest subset whose pairwise absolute differences sum to at most S.	Medium5	SortingSliding window+1	No attempts yet	1s	1024 MB	Judgeable
Square PenGiven a grid of free cells and obstacles, find the area of the largest all-free square subgrid.	Medium5	MatrixDynamic programming	No attempts yet	1s	1024 MB	Judgeable
SemiperfectFor each integer m below 1,000,000, decide whether some subset of its proper divisors sums to m.	Medium5	Dynamic programmingMath+1	No attempts yet	1s	1024 MB	Judgeable
RepeatFor each string, find the longest substring that appears twice without overlapping, and print its length and the earliest such substring.	Medium5	StringDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
God of BattleGiven a budget N and two mercenary types with power A and B and costs PA and PB, find the counts x and y that maximize Ax+By within the budget.	Medium5	GreedyBrute force+1	No attempts yet	1s	1024 MB	Judgeable
map, filterApply a sequence of map and filter commands to an array of N integers and print the size of the array after each filter.	Medium5	ArrayHash map+1	No attempts yet	1s	1024 MB	Judgeable
Find the permutationGiven array B, built by XORing the sorted prefixes of a permutation P together with P, the task is to recover P.	Medium5	ImplementationSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Shiroko and the Bank RobberyPick k of n applicants, where each pair of values sums to x, to maximize the product of the total a and the total b.	Medium5	Dynamic programmingMath	No attempts yet	1s	512 MB	Judgeable
Polish LanguageCount the substrings of a lowercase string that contain three consecutive consonants or three consecutive vowels, counting each position separately.	Medium5	StringSliding window+1	No attempts yet	1s	1024 MB	Judgeable
New ContractGiven N integers, find the fewest total digits to append to them so that the resulting sequence is strictly increasing.	Medium5	GreedyMath	No attempts yet	2s	1024 MB	Judgeable
GramfanCount the substrings of S that contain all 26 letters, with the letters in non-decreasing alphabetical order.	Medium5	Two pointersSliding window+1	No attempts yet	1s	1024 MB	Judgeable
Diagnostic 0 : 1Count integers k in [a, b] whose base-m digit sum equals n, for up to 50,000 test cases.	Medium5	Dynamic programmingMath	No attempts yet	2s	1024 MB	Judgeable
Power Plants and FactoriesConnect power plants and factories placed on a line of n cities with adjacent grid segments, minimizing total segment length so every factory gets its demand.	Medium5	Prefix sumArray	No attempts yet	2s	1024 MB	Judgeable
Delivery VansGiven delivery vans that leave garages on avenues or streets, find the fewest vans to cancel so no two remaining vans share an intersection at the same moment.	Medium5	Hash mapMath	No attempts yet	2s	1024 MB	Judgeable
OranżadaGiven n bottles in a row, find the fewest adjacent swaps that make the first k bottles all have different brands, or report -1 if impossible.	Medium5	GreedyHash map+1	No attempts yet	1s	1024 MB	Judgeable
Ornitolog 2Given a sequence of pitches, find the fewest notes to replace so that the pitches strictly alternate between rising and falling.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
Agar.ioFind the fewest absorptions for a cell starting at mass 2 to reach or match the largest opponent mass, absorbing only cells smaller than itself.	Medium5	GreedySorting+1	No attempts yet	1.5s	1024 MB	Judgeable
LollipopFind the shortest contiguous piece in which some flavor appears at least three times, or report NIE if no such piece exists.	Medium5	Sliding windowHash map	No attempts yet	4s	1024 MB	Judgeable
Smallest SumGiven digit tiles, build exactly K positive integers without leading zeros so that their total sum is as small as possible.	Medium5	GreedySorting+1	No attempts yet	0.5s	1024 MB	Judgeable
High-Heeled Flip-FlopsGiven people's heights and flip-flop heel heights, find the maximum number of people who can reach height T, with each person wearing at most one pair.	Medium5	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
AntipalindromeCount the contiguous substrings of the given word that contain no palindrome of length 2 or more.	Medium5	StringSliding window+1	No attempts yet	1s	1024 MB	Judgeable
Fine OptimizationPair each speed value K with one service number R so that the sum of the concatenated digit strings is as small as possible, then print that minimum.	Medium5	GreedySorting	No attempts yet	10s	1024 MB	Judgeable
Alternating Word IICount the length-3 subsequences whose adjacent letters differ, and count the distinct three-letter alternating words they spell.	Medium5	Dynamic programmingString	No attempts yet	8s	1024 MB	Judgeable
Strong NumbersFor each query interval [A, B] with B up to 10^13, sum every number that is a sum of distinct factorials inside that interval.	Medium5	Bit manipulationPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
PoolGiven N distance readings from the shore, find the minimum number of pool lengths Bajtek must have swum to produce them.	Medium5	GreedyImplementation	No attempts yet	6s	1024 MB	Judgeable
The Boards Strike BackFind the largest side s so that boards cut into pieces of length s yield at least four pieces, then print s squared.	Medium5	Binary searchMath	No attempts yet	3s	1024 MB	Judgeable
MinusyGiven a string of + and -, repeatedly turn two adjacent - into +, and find the longest run of adjacent + that can be formed.	Medium5	StringTwo pointers+1	No attempts yet	5s	1024 MB	Judgeable
Unlucky NumbersCount the numbers from 1 to N whose digits sum to 13 and whose decimal form contains the substring 13.	Medium5	Dynamic programmingString	No attempts yet	12s	1024 MB	Judgeable
ZigzagGiven a string of P and G moves, check whether it is the greedy zigzag under the diagonal of some fraction p/q, and print that fraction in lowest terms or NIE.	Medium5	SimulationMath	No attempts yet	5s	1024 MB	Judgeable
Video EditorChoose as many videos as possible that can be edited one at a time before their deadlines, and print each chosen video's start day.	Medium5	GreedySorting+1	No attempts yet	4s	1024 MB	Judgeable
Sum of PrimesGiven N, find a contiguous run of consecutive primes whose sum is exactly N, or print NIE if no such run exists.	Medium5	Two pointersSliding window+1	No attempts yet	15s	1024 MB	Judgeable
SzarlotkaGiven N integers, find the non-empty contiguous subarray whose sum is closest to K and print the minimum \|sum - K\|.	Medium5	Prefix sumBinary search	No attempts yet	5s	1024 MB	Judgeable
CrosswordGiven N dictionary words and Q patterns where ? matches any one letter, print the matching word if there is exactly one, otherwise the number of matches.	Medium5	Hash mapString matching+1	No attempts yet	10s	1024 MB	Judgeable
WyliczankaGiven N children in a circle and step counts X1 to XN, the task is to output the order in which children leave, each round removing the child reached by the Xi-th tap.	Medium5	ArraySimulation+1	No attempts yet	6s	1024 MB	Judgeable
Making It SmallerGiven A, B, and k, change exactly k digits of A to get the largest number smaller than B, or report -1 if no such number exists.	Medium5	GreedyString+1	No attempts yet	5s	1024 MB	Judgeable
Metro PlanGiven distances from stations 1 and n to every other station, build a tree of n-1 tunnels that matches both lists, or report NIE if none exists.	Medium5	SortingTree+1	No attempts yet	2s	1024 MB	Judgeable
LawyersGiven n lawyers' free intervals, pick k lawyers so their shared free time is as long as possible, then print that length and the chosen lawyer numbers.	Medium5	IntervalsHeap+1	No attempts yet	2s	1024 MB	Judgeable
XOR PairsCount ordered pairs (A, B) where A and B are at most A XOR B, A XOR B is at most N, and A XOR B is not in the set S.	Medium5	Bit manipulationMath+1	No attempts yet	1s	1024 MB	Judgeable
Not OneGiven a weighted tree, find the size of the largest connected subtree whose node weights have a GCD other than 1.	Medium5	TreeNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Maxdifficent GroupSplit the array into contiguous groups and find the largest cost gap between two adjacent groups over all splits.	Medium5	Prefix sumImplementation	No attempts yet	1s	1024 MB	Judgeable
Bricks in the WallGiven a grid of bricks and empty cells, find two non-overlapping horizontal or vertical runs of empty cells with the largest total length.	Medium5	MatrixImplementation+1	No attempts yet	2s	1024 MB	Judgeable
SkridskorFind the fewest turns for a skater who glides straight until hitting an obstacle, then turns left or right, to exit the east edge of a grid.	Medium5	BFSShortest path+1	No attempts yet	1s	1024 MB	Judgeable
PortalsEach portal leads to exactly one destination, and for each query the task is to count the jumps from start s to end e, or report -1 if e is never reached.	Medium5	GraphTree+1	No attempts yet	1s	1024 MB	Judgeable
The ExpressionGiven an expression of non-negative integers joined by +, -, and *, find the largest value reachable by evaluating adjacent pairs in any order.	Medium5	Dynamic programming	No attempts yet	1s	1024 MB	Judgeable
Cave EscapeFind a move sequence that takes you from S to the exit U through a wall grid without sharing a cell with the bear, which moves up to 2 steps toward you each turn.	Medium5	BFSSimulation	No attempts yet	1s	1024 MB	Judgeable
Dance MatFind the fewest foot moves needed to press every required arrow in a song, where each measure lists one or two arrows and the feet start on left and right.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
FotografenGiven N photos with rotations, find the fewest operations that rotate k adjacent photos clockwise at once to make all upright, or -1 if impossible.	Medium5	GreedyPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Nice NumbersCount the ways to delete digits from a number of up to 100,000 digits so the remaining number is divisible by 3, modulo 10^9.	Medium5	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
OrienteeringFind the fewest arrows Springoalla must skip so that she ends at a given cell, starting at the top left moving right.	Medium5	GraphBFS+1	No attempts yet	6s	1024 MB	Judgeable
Sock Matching 2Given N sock colors, find the smallest D so that at least K pairs of socks have a color difference strictly less than D.	Medium5	SortingBinary search+1	No attempts yet	4s	1024 MB	Judgeable
The board gameTwo players alternately cut an N x M board along integer lines, and the opponent keeps one piece. Decide who wins with optimal play.	Medium5	Game theoryMath	No attempts yet	1s	1024 MB	Judgeable
SpringoallaGiven n tracks with round-trip times, choose full and half runs so the total time is at least t and as small as possible, using the fewest runs on ties.	Medium5	Dynamic programmingGreedy	No attempts yet	5s	1024 MB	Judgeable
Summa SummarumGiven two equal-length integer lists, swap one element between them exactly once to minimize the absolute difference of their sums.	Medium5	Binary searchSorting	No attempts yet	5s	1024 MB	Judgeable
BookshelvesGiven counts of small, medium, and large books and the shelf size, find the fewest shelves needed to hold all books without splitting any book.	Medium5	Dynamic programming	No attempts yet	1s	1024 MB	Judgeable
TivoliPick one facility per attraction and an visiting order that gives the shortest closed walk from the origin, with N up to 15.	Medium5	Dynamic programmingBit manipulation	No attempts yet	1s	1024 MB	Judgeable
Ant ColonyGiven a tree of unit tunnels on a grid, count the connected components left inside each query rectangle when the outside points are removed.	Medium5	Prefix sumSorting+1	No attempts yet	1s	1024 MB	Judgeable
Feeding the CowsPlace the fewest grass patches so every cow has a patch of its own breed within K positions, then print one valid layout.	Medium5	GreedyImplementation	No attempts yet	2s	1024 MB	Judgeable
Treats for the CowsGiven N treat values in a box open at both ends, find the maximum revenue when each treat is sold from either end with its value times its age.	Medium5	Dynamic programmingTwo pointers	No attempts yet	1s	1024 MB	Judgeable
Stall ReservationsAssign each cow's closed time interval A to B to a stall so that overlapping cows never share one, using the fewest stalls and reporting the assignment.	Medium5	GreedyHeap+2	No attempts yet	1s	1024 MB	Judgeable
Redundant PathsGiven fields connected by paths, find the fewest new paths so every pair of fields has two routes that share no path.	Medium5	GraphDFS+1	No attempts yet	1s	1024 MB	Judgeable
Corral the CowsFind the smallest side length of an axis-parallel square that covers at least C of the N clover fields, each a 1 by 1 cell.	Medium5	Binary searchPrefix sum	No attempts yet	1s	1024 MB	Judgeable
The GroveFind the fewest 8-directional steps for Bessie to walk around the grove of X cells and return to her start in an R by C grid.	Medium5	BFSGraph	No attempts yet	1s	1024 MB	Judgeable
Knights of NiFind the fewest moves for Bessie to walk from her start to any shrubbery, then from that shrubbery to the Knights of Ni, on a grid with blocked squares.	Medium5	BFSMatrix+1	No attempts yet	1s	1024 MB	Judgeable
ScalesGiven N weights where each one is at least the sum of the two before it, find the largest subset sum that does not exceed the limit C.	Medium5	GreedyBacktracking	No attempts yet	1s	1024 MB	Judgeable
SkiingFind the minimum time to ski from the top-left to the bottom-right cell of a grid, where speed changes by a power of two with each elevation step.	Medium5	Shortest pathGraph+1	No attempts yet	1s	1024 MB	Judgeable
Yogurt factoryGiven weekly production costs, delivery quantities, and a per-week storage fee, find the minimum total cost to meet every week's delivery.	Medium5	GreedyDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Cube StackingStarting from N single-cube stacks, process moves that place one stack on top of another and queries that count the cubes beneath a given cube.	Medium5	Union-findArray	No attempts yet	2s	1024 MB	Judgeable
Turning in HomeworkFind the earliest second Bessie can reach the bus door at position B after turning in homework at each classroom, which accepts it only from its given time.	Medium5	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Paranoid CowsGiven N time intervals, find the largest K such that the first K intervals contain no pair where one strictly contains another.	Medium5	SortingBinary search	No attempts yet	1s	1024 MB	Judgeable
BreedingCount the ordered sequences of factors, each at least 2, whose product is N, since each generation multiplies the herd by its calf count.	Medium5	Dynamic programmingNumber theory	No attempts yet	1s	1024 MB	Judgeable
Pesky ParenthesesGiven N signed terms, find the largest value the expression can reach under any placement of parentheses.	Medium5	GreedyBrute force	No attempts yet	1s	1024 MB	Judgeable
Cow ExhibitionChoose a subset of cows so that total smartness and total funness are both non-negative, and maximize their sum.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Milking GridGiven an R by C grid of letters, find the smallest-area rectangle that, repeated and cut off at the edges, rebuilds the whole grid.	Medium5	StringString matching+1	No attempts yet	1s	1024 MB	Judgeable
Popular CowsGiven M directed pairs (A, B) meaning cow A thinks cow B is popular, count the cows that every other cow can reach through transitive popularity.	Medium5	GraphDFS+1	No attempts yet	1s	1024 MB	Judgeable
Beauty ContestGiven N integer points in the plane, find the largest squared distance between any two of them.	Medium5	GeometrySorting	No attempts yet	1s	1024 MB	Judgeable