Interview warm-up

Short whiteboard warmups

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Still being built. Things may change

Total results4,880 problems

Circumference of a Circle
Easy3
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Soccer Tournament
Easy3
Implementation, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Read the Chessboard
Easy3
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Complicated Route
Easy3
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Too Much Water
Easy3
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Goldbach's Conjecture
Easy3
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Add Backward Numbers
Easy3
Math, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Next Year with Distinct Digits
Easy3
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chances of Winning
Easy3
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Aromatic Numbers
Easy3
String, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Absolutely Acidic
Easy3
Array, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Mouse Journey
Easy3
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Who Has Seen the Wind
Easy3
Math, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Up and Down
Easy3
Simulation, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Punchy
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Global Warming
Easy3
String matching, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Huffman Encoding
Easy3
Trie, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Signage
Easy3
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
GPS Text Entry
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cell-Phone Messaging
Easy3
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maternity
Easy3
Implementation, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
RSA Numbers
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Returning Home
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fix-Free Check
Easy3
String, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
TopYodeller
Easy3
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Picture Perfect
Easy3
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Snakes and Ladders
Easy3
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Poetry
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Students' Council Breakfast
Easy3
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Numbers That Read the Same Upside Down
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Slot Machines
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Babbling Brooks
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card Game
Easy3
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Censor
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Deficient, Perfect, and Abundant
Easy3
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Train Swapping
Easy3
Array, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trimmed and Corrected Mean
Easy3
Sorting, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Arithmetic Sequence
Easy3
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hobbiton Farms
Easy3
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Guessing Game I
Easy3
Implementation, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Milk and Honey
Easy3
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Class
Easy3
Implementation, Matrix+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mõttemeister
Easy3
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Carpets
Easy3
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Harmony: Parallel Fifths
Easy3
Implementation, Array+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Harmony
Easy3
Implementation, Brute force+2
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Aliens' Socks
Easy3
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Alien Socks
Easy3
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Attendance Check
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shampoo
Easy3
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pyramids
Easy3
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sled
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Animals
Easy3
Intervals, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Couriers
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sorting
Easy3
Sorting, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Laundry
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bus
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Scrabble Scoring
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Skew Binary
Easy3
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Steps
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Web Navigation
Easy3
Stack, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Undercut
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ride My Bicycle
Easy3
Sorting, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sequence
Easy3
Math, Brute force
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Untidy Desktops
Easy3
Geometry, Brute force
No attempts yet
Time limit
7s
Memory limit
128 MB
Judgeable
Box
Easy3
Implementation, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Easy Trading
Easy3
Array, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Social Networking Application
Easy3
Union-find, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Prehistoric Operating Systems
Easy3
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stamps
Easy3
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Body Size Ranking
Easy3
Array, Brute force
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Chosen Sub Matrix
Easy3
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Email from the Professor
Easy3
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Simple Prefix Compression
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Intervals
Easy3
Sorting, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Dance
Easy3
Graph, DFS
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chaos and the Stonki
Easy3
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Scale
Easy3
Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Network Investment
Easy3
DFS, Tree
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Program
Easy3
Stack
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
The Hare
Easy3
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Necklaces
Easy3
Simulation, String
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Postcard
Easy3
Combinatorics, Array
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
The Tape
Easy3
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
List
Easy3
Math, Array
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Smallest Missing Multiple
Easy3
Hash map, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Sorting the Jewelry
Easy3
Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Shop
Easy3
Hash map
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Smallest Perfect-Square Multiple
Easy3
Number theory
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lottery
Easy3
Greedy, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Passing Cars
Easy3
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grasshopper
Easy3
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Bet
Easy3
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nails
Easy3
Sorting, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grasshopper 2
Easy3
Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Forest
Easy3
Hash map
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dividers
Easy3
Array, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Taps
Easy3
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Towers
Easy3
Greedy, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Cheerful Monkey
Easy3
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Circumference of a CircleFor each line of three non-collinear points, compute the perimeter of the circle passing through them, rounded to two decimals.	Easy3	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Soccer TournamentRead team lists and played games, then print a result grid and a standings table sorted by points, goal difference, goals, wins, and reverse input order.	Easy3	ImplementationSorting	No attempts yet	1s	128 MB	Judgeable
Read the ChessboardGiven an ASCII-art chessboard, list each side's pieces in standard notation, grouped by type in a fixed order and sorted by position rules.	Easy3	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
Complicated RouteParse a route of step counts in eight compass directions, sum the displacement, and print the final point and its distance from the origin to three decimals.	Easy3	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
Too Much WaterGiven a property point, compute the hour when the growing semicircle centered at the origin first covers it, using the fixed 50 square meters per hour rate.	Easy3	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Goldbach's ConjectureFor each even n below 2^15, count the unordered pairs of primes that sum to n, stopping at a terminating 0.	Easy3	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Add Backward NumbersAdd two numbers whose digits are given in reverse order, printing the sum with its digits also reversed and no leading zeroes.	Easy3	MathString+2	No attempts yet	1s	128 MB	Judgeable
The Next Year with Distinct DigitsGiven a year Y, print the smallest year greater than Y whose decimal digits are all distinct.	Easy3	Brute forceImplementation	No attempts yet	1s	128 MB	Judgeable
Chances of WinningGiven results of some games among four teams, count the outcomes of the remaining games where team T ends with strictly more points than every other team.	Easy3	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Aromatic NumbersGiven a string alternating Arabic digits and Roman numeral letters, sum each digit times its Roman value, subtracting a pair when the next Roman value is larger.	Easy3	StringImplementation+1	No attempts yet	2s	512 MB	Judgeable
Absolutely AcidicCount the frequency of readings in the range 1 to 1000, then apply tie-breaking rules to find which two readings to subtract.	Easy3	ArrayImplementation+1	No attempts yet	2s	512 MB	Judgeable
Mouse JourneyCount monotone right/down paths on an R by C grid from (1,1) to (R,C) that avoid K blocked cat cells.	Easy3	Dynamic programmingMatrix+1	No attempts yet	2s	512 MB	Judgeable
Who Has Seen the WindGiven humidity h and a time limit M, evaluate the quartic altitude formula hour by hour and report the first hour the balloon's altitude drops to zero or below.	Easy3	MathSimulation+2	No attempts yet	2s	512 MB	Judgeable
Up and DownTwo walkers repeat a forward/backward step cycle; after s steps, report whose distance from the start is greater, or Tied.	Easy3	SimulationMath+2	No attempts yet	2s	512 MB	Judgeable
PunchySimulate a tiny two-variable language, running the given instructions in order until a stop opcode, and print each requested variable value.	Easy3	SimulationImplementation+1	No attempts yet	2s	512 MB	Judgeable
Global WarmingGiven a sequence of temperatures, find the length of the shortest period of the sequence of consecutive differences, allowing the final repetition to be truncated.	Easy3	String matchingBrute force+2	No attempts yet	2s	512 MB	Judgeable
Huffman EncodingGiven prefix-free binary codes for up to 20 letters, decode a binary string of at most 250 digits back into the original letters.	Easy3	TrieString+2	No attempts yet	2s	512 MB	Judgeable
SignageGiven a sign width, lay out a fixed sentence into lines, justifying each line so spaces are spread as evenly as possible, and print dots for spaces.	Easy3	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
GPS Text EntryGiven a fixed 5x6 letter grid, compute the total cursor moves to type a string starting from 'A' and then reach 'enter'.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Cell-Phone MessagingGiven words, compute the typing time on a phone keypad where each press takes 1 second and switching between letters on the same key adds a 2-second pause.	Easy3	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
MaternityGiven the two alleles each parent carries for five genes, decide for each baby whether its five visible traits could result from that pairing.	Easy3	ImplementationCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
RSA NumbersCount how many integers in an inclusive range below 1000 have exactly four divisors, then print the count in a fixed sentence.	Easy3	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Returning HomeReverse a short list of turn directions and street names, flipping each left or right turn, to produce the route from school back home.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Fix-Free CheckFor each triple of words, decide whether no word is a prefix or suffix of another, printing Yes or No.	Easy3	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
TopYodellerCompute each yodeller's cumulative score after every round, find who ends with the highest total, and report their worst rank.	Easy3	ArraySimulation+1	No attempts yet	1s	128 MB	Judgeable
Picture PerfectFor each C, find the factor pair (W, H) with W*H = C closest to a square, and report the smallest perimeter along with W and H.	Easy3	MathBrute force+2	No attempts yet	1s	128 MB	Judgeable
Snakes and LaddersSimulate a Snakes and Ladders game with a fixed 100-square board, applying three given ladders and three given snakes after each dice roll until the piece reaches 100 or the player quits.	Easy3	SimulationImplementation	No attempts yet	1s	128 MB	Judgeable
PoetryFor each four-line verse, extract the last syllable of the final word on every line and print which rhyme scheme it matches.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
The Students' Council BreakfastGiven four ticket prices and a target amount, list every non-negative count combination that hits the target, count them, and report the fewest tickets needed.	Easy3	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Numbers That Read the Same Upside DownCount how many integers in the interval [m, n] stay the same when rotated 180 degrees, using the digit map 0, 1, 8, 6, 9.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Slot MachinesSimulate a gambler who cycles through three slot machines with fixed payout periods and stops when she runs out of quarters, and report the total number of plays.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Babbling BrooksSimulate a sequence of splits and joins on a list of streams and print the resulting flows after each split divides flow by a percentage and each join merges neighbors.	Easy3	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Card GameSimulate a 52-card game where players alternate turning cards; award points when a high card is followed by enough non-high cards, then print each score.	Easy3	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
CensorRead n lines of space-separated words and replace every word of exactly four letters with ****, printing a blank line between consecutive output lines.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Deficient, Perfect, and AbundantFor each integer, sum its proper divisors and classify it as deficient, perfect, or abundant.	Easy3	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Train SwappingFor each test case, count the inversions of a permutation of 1..L, the minimum number of adjacent swaps needed to sort the train.	Easy3	ArraySorting+2	No attempts yet	1s	128 MB	Judgeable
Trimmed and Corrected MeanGiven N judge scores and an integer K, sort the scores, then output the trimmed mean that drops K from each end and the corrected mean that replaces those extremes with the nearest kept value, both rounded to two decimals.	Easy3	SortingPrefix sum+2	No attempts yet	1s	256 MB	Judgeable
Arithmetic SequenceGiven a sequence, decide whether consecutive differences are equal and, if so, print the next five terms in the exact required format.	Easy3	ImplementationMath+1	No attempts yet	1s	128 MB	Judgeable
Hobbiton FarmsFor each test case, decide whether a circle and an axis-aligned rectangle share at least one point.	Easy3	GeometryImplementation+1	No attempts yet	1s	128 MB	Judgeable
Guessing Game ICompare a 4-digit secret and a guess digit by digit, count exact-position matches as circles and remaining cross-position matches as squares, with duplicates matched once.	Easy3	ImplementationHash map+2	No attempts yet	1s	128 MB	Judgeable
Milk and HoneyEach field holds either cows up to its cow limit or bees up to its bee limit; assign each field one animal type to maximize happiness from milk and honey.	Easy3	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
ClassGiven a grid of digits, sum each cell's average absolute difference from its up to four orthogonal neighbors, and print the total with four decimals.	Easy3	ImplementationMatrix+2	No attempts yet	1s	1024 MB	Judgeable
MõttemeisterGiven a secret four-digit number and N guesses, print for each guess the count of correct digits (A) and the count of digits in the correct position (B).	Easy3	ImplementationArray+2	No attempts yet	1s	1024 MB	Judgeable
CarpetsGiven up to three axis-aligned rectangles, find the total area of their union.	Easy3	GeometryImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Harmony: Parallel FifthsGiven N pairs of simultaneous two-voice pitches, list every position i where the voices form a perfect fifth (interval 5 mod 12) at both i and i+1 and both voices move.	Easy3	ImplementationArray+2	No attempts yet	3s	1024 MB	Judgeable
HarmonyGiven K voices over N note rows, list every pair of consecutive rows and voice pair that forms a parallel fifth (both voices move and stay 7 semitones apart mod 12).	Easy3	ImplementationBrute force+2	No attempts yet	7s	1024 MB	Judgeable
Aliens' SocksFind the minimum number of socks to draw so that at least k of one color are guaranteed, given the counts per color.	Easy3	GreedyMath+1	No attempts yet	1s	1024 MB	Judgeable
Alien SocksGiven counts of socks in s colors, find the smallest number of socks to draw to guarantee k socks of one color, or -1 if impossible.	Easy3	MathGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Attendance CheckGiven a permutation forming one cycle, find the student who responds last when the calling chain starts at student k.	Easy3	ImplementationSimulation+2	No attempts yet	1s	1024 MB	Judgeable
ShampooGiven N days and a sorted list of holidays, count how many days residents wash their hair under the stated daily rules.	Easy3	ImplementationSimulation	No attempts yet	1s	1024 MB	Judgeable
PyramidsGiven N blocks, repeatedly take out the largest triangular number that fits, and print the resulting pyramid heights in decreasing order.	Easy3	GreedyMath+2	No attempts yet	1s	1024 MB	Judgeable
SledSimulate a sled whose speed changes by a_i on each segment and drops by 1 at junctions whenever it exceeds S; report the final speed.	Easy3	SimulationImplementation+1	No attempts yet	1s	1024 MB	Judgeable
AnimalsGiven N active time intervals, find whether they share a common moment and, if so, the longest interval when all animals are active.	Easy3	IntervalsImplementation+2	No attempts yet	1s	1024 MB	Judgeable
CouriersSimulate two couriers who each take an incoming order if free, preferring the faster one, and total each courier's earnings.	Easy3	SimulationImplementation+1	No attempts yet	1s	1024 MB	Judgeable
SortingA full comparison table between two hidden permutations of 1..N is given; recover the value on every card.	Easy3	SortingImplementation	No attempts yet	1s	1024 MB	Judgeable
LaundryGiven colors partitioned into washable groups and counts of clothes per color, find how many machine loads of capacity M are needed.	Easy3	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
BusTrack how many passengers are on the bus after each stop and report the largest number of them that exceeds the seat count K.	Easy3	ImplementationSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Scrabble ScoringScore each Scrabble play by parsing its start square and direction, applying letter and word bonus multipliers from the fixed 15x15 board.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Skew BinaryConvert each decimal number into its unique skew binary representation, printed as the sorted ranks of its nonzero digits.	Easy3	MathGreedy+2	No attempts yet	1s	128 MB	Judgeable
Number StepsGiven a point, print the number written there by a fixed boustrophedon path over the plane, or No Number if the point is empty.	Easy3	MathImplementation	No attempts yet	1s	128 MB	Judgeable
Web NavigationSimulate browser back and forward navigation using two stacks, printing the current URL after each command.	Easy3	StackSimulation+1	No attempts yet	1s	128 MB	Judgeable
UndercutScore a five-round card game where players reveal numbered cards each round, applying undercut and tie rules, and print both totals.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Ride My BicycleCompute the ratio of each of the 21 front and back gear pairs, round to two decimals, and print them sorted by ratio then chain ring.	Easy3	SortingImplementation+1	No attempts yet	1s	128 MB	Judgeable
SequenceGiven up to five strictly increasing numbers, find the smallest base at most 10 in which their values, read as base-b numerals, form an arithmetic sequence.	Easy3	MathBrute force	No attempts yet	1s	128 MB	Judgeable
Untidy DesktopsGiven n axis-aligned rectangles, count how many overlap at least one other rectangle, boundaries included.	Easy3	GeometryBrute force	No attempts yet	7s	128 MB	Judgeable
BoxGiven six rectangles that can be rotated, decide whether they form the three pairs of opposite faces of a rectangular box.	Easy3	ImplementationSorting+1	No attempts yet	2s	128 MB	Judgeable
Easy TradingGiven daily prices, compute moving averages over the last m and n days and print a buy or sell signal whenever the trend between them reverses.	Easy3	ArrayPrefix sum+2	No attempts yet	2s	128 MB	Judgeable
Social Networking ApplicationGiven a friendship graph, answer queries asking whether two users lie in the same connected component.	Easy3	Union-findGraph+2	No attempts yet	1s	128 MB	Judgeable
Prehistoric Operating SystemsCount binary strings of length n with no two adjacent D's, where D means DOORS and O means any other brand, for up to 40 test values of n.	Easy3	Dynamic programmingCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
StampsGiven a needed stamp count and each friend's offer, find the fewest friends whose offers sum to at least the needed amount, or report impossible.	Easy3	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Body Size RankingFor each person, count how many others are both heavier and taller, and print that count plus one.	Easy3	ArrayBrute force	No attempts yet	1s	128 MB	Judgeable
The Chosen Sub MatrixFor each N x N matrix, find the M x M sub matrix with the fewest distinct values, breaking ties by larger descending value lists, then by smaller top-left row and column.	Easy3	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Email from the ProfessorWrite each message row by row into a grid of width k, then read columns in the order given by a permutation key, dropping padding cells.	Easy3	ImplementationArray+2	No attempts yet	1s	128 MB	Judgeable
Simple Prefix CompressionSum stored lengths after prefix compression: each string stores a control byte plus the part not shared as a prefix with the previous string.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
IntervalsGiven n closed intervals, merge all overlapping or touching ones and print the resulting disjoint intervals in ascending order.	Easy3	SortingIntervals+2	No attempts yet	1s	128 MB	Judgeable
The DanceFind the largest number of boy-girl pairs that can dance at once when each boy may only invite a girl he knows.	Easy3	GraphDFS	No attempts yet	1s	128 MB	Judgeable
Chaos and the StonkiEach entry is a name with hyphens inserted anywhere and letters possibly lowercased; count how many distinct real names (uppercase only) appear.	Easy3	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
Binary ScaleSort the given (reading, precision) pairs by reading divided by 2 to the precision, breaking ties by smaller reading.	Easy3	Sorting	No attempts yet	1s	128 MB	Judgeable
Network InvestmentFind the tree edge whose removal maximizes the product of the two component sizes.	Easy3	DFSTree	No attempts yet	1s	128 MB	Judgeable
ProgramCheck whether the bracket string is correct and print its maximum nesting depth, or NIE when it is not.	Easy3	Stack	No attempts yet	1s	512 MB	Judgeable
The HareFind the fewest knight jumps from the start cell to the burrow on a grid with blocked cells, or output NIE when unreachable.	Easy3	BFSGraph+1	No attempts yet	1s	512 MB	Judgeable
NecklacesSplit each circular necklace string into runs of equal size and shade and report the longest and shortest run, preferring larger then lighter beads on ties.	Easy3	SimulationString	No attempts yet	1s	512 MB	Judgeable
PostcardCount the contiguous segments that keep at least one mountain of height m or more after trimming both ends.	Easy3	CombinatoricsArray	No attempts yet	1s	512 MB	Judgeable
The TapeFind the largest distance between two positions holding different values in each test case, printing BRAK if all values are equal.	Easy3	GreedyArray	No attempts yet	1s	512 MB	Judgeable
ListAfter moving the last k numbers of 1 to n to the front, sum the entries from position i to position j.	Easy3	MathArray	No attempts yet	1s	512 MB	Judgeable
Smallest Missing MultipleFind the smallest positive multiple of k that is absent from the given set of n distinct integers.	Easy3	Hash mapMath	No attempts yet	1s	512 MB	Judgeable
Sorting the JewelrySort up to 150 lowercase strings by increasing length, breaking ties in lexicographic order.	Easy3	Sorting	No attempts yet	1s	512 MB	Judgeable
ShopAdd up the quantities for each product number and print the totals in first-appearance order.	Easy3	Hash map	No attempts yet	2s	512 MB	Judgeable
Smallest Perfect-Square MultipleRead n and print the smallest multiple of n that is a perfect square.	Easy3	Number theory	No attempts yet	1s	128 MB	Judgeable
LotteryChange as few letters of the given A, B, or C string as possible so no two neighbors match.	Easy3	GreedyString	No attempts yet	1s	128 MB	Judgeable
Passing CarsCount pairs of cars moving toward each other where an eastbound car stands west of a westbound car.	Easy3	Prefix sumArray	No attempts yet	1s	128 MB	Judgeable
GrasshopperThe grasshopper crosses width x with the fewest jumps, starting at length s and halving each later jump rounded down, with 1 always allowed.	Easy3	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
The BetTurn the fewest dice so exactly k of the six faces appear, keeping the most frequent faces and adding missing ones.	Easy3	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
NailsLower at most k nails to match a chosen height and maximize how many nails share that height.	Easy3	SortingGreedy	No attempts yet	1s	128 MB	Judgeable
Grasshopper 2Decide whether jumps of lengths s, s/2, s/4, and so on can reach or pass distance x in finitely many jumps.	Easy3	Math	No attempts yet	1s	128 MB	Judgeable
ForestCount distinct species, since the thickest tree of each species could be the oldest.	Easy3	Hash map	No attempts yet	1s	128 MB	Judgeable
DividersCount the positions where the first k entries hold exactly 1 to k by tracking the running maximum.	Easy3	ArrayGreedy	No attempts yet	1s	128 MB	Judgeable
TapsClose the fewest flowing taps so the average temperature of the water still flowing reaches at least w.	Easy3	GreedySorting	No attempts yet	1s	128 MB	Judgeable
Two TowersRemove the fewest blocks from the tops of two towers so the remaining towers have equal height.	Easy3	GreedyTwo pointers+1	No attempts yet	1s	128 MB	Judgeable
The Cheerful MonkeyStarting from one closed cage in a circle of n, repeated jumps of length d open each landing cage until a repeat, and you count the opened cages.	Easy3	Number theoryMath	No attempts yet	1s	128 MB	Judgeable