Problems
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Total results1,786 problems
| Title | Level | Topics | Solved | Time limit | Memory limit | Judge |
|---|---|---|---|---|---|---|
| Progressive ScrambleEncrypt a message by cumulative sums of symbol values mod 27, and decrypt by inverting the same recurrence. | Easy3 | ImplementationMath+2 | No attempts yet | 2s | 512 MB | Judgeable |
| Vera and ABCDEGiven a string of N letters from A to E, render the 5x3 pattern for each letter side by side and print the resulting 5 rows of 3N characters. | Easy3 | ImplementationString+2 | No attempts yet | 2s | 512 MB | Judgeable |
| IDN Homograph AttackGiven a string, decide whether some character can be swapped for a different character that normalizes to the same form. | Easy3 | StringHash map+2 | No attempts yet | 1s | 256 MB | Judgeable |
| Send me the moneyGiven a pattern string S, decide for each of M notes whether S is a subsequence of the note. | Easy3 | StringTwo pointers+2 | No attempts yet | 1s | 512 MB | Judgeable |
| A+B Without SpacesA string holds two numbers from 1 to 10 with no separator; find a split that makes two valid natural numbers and print their sum. | Easy3 | StringBrute force+1 | No attempts yet | 0.5s | 512 MB | Judgeable |
| A Palindrome Is Not a Palindrome!!Given an uppercase string up to 500,000 characters, find the length of the longest substring that is not a palindrome, or -1 if none exists. | Easy3 | StringImplementation+2 | No attempts yet | 2s | 512 MB | Judgeable |
| Baby Sukhwan Tururu TuruFind the N-th word of a repeating song whose tururu runs grow by one extra ru each repetition, with long runs printed in a compressed form. | Easy3 | ImplementationMath+2 | No attempts yet | 1s | 512 MB | Judgeable |
| Girl Group Master JunseokRead N girl groups with member lists, then answer M quizzes: list a team's members sorted, or name a member's team. | Easy3 | Hash mapSorting+1 | No attempts yet | 2s | 128 MB | Judgeable |
| I Have Few Friends (Small)A textbook text S may contain digits that stand for unknown letters. Decide whether a keyword K (letters only) can match some substring of S, treating each digit as any letter. | Easy3 | StringBrute force+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Variable NamesGiven a variable name in camel, snake, or Pascal case, print its camel, snake, and Pascal forms. | Easy3 | StringImplementation | No attempts yet | 2s | 512 MB | Judgeable |
| SpreadsheetsConvert a column index up to 1e9 into a base-26 name like A, Z, AA, using letters with no zero digit. | Easy3 | MathString+2 | No attempts yet | 2s | 512 MB | Judgeable |
| Go LatinTranslate each English word to pseudo-Latin by replacing the suffix per a table, or appending "us" when no listed suffix matches. | Easy3 | StringImplementation | No attempts yet | 0.5s | 512 MB | Judgeable |
| ExamGiven two answer strings and how many answers your friend got right, maximize your own possible score over all valid answer keys. | Easy3 | StringGreedy+1 | No attempts yet | 2s | 512 MB | Judgeable |
| EnigmaCount alignments of the crib inside the ciphertext where no crib letter equals the ciphertext letter at the same offset. | Easy3 | StringBrute force+1 | No attempts yet | 2s | 512 MB | Judgeable |
| Season of ReadingReplace WHO, WHERE, and WHAT in each sentence with the given resolving elements, expanding nested references. | Easy3 | StringRecursion+1 | No attempts yet | 1s | 512 MB | Judgeable |
| Grouping Identical WordsCount words that are permutations of each other using letter counts, and print the number of distinct letter multisets. | Easy3 | SortingHash map+1 | No attempts yet | 2s | 512 MB | Judgeable |
| Aligned TypesettingGiven an equal number of spaces between every pair of consecutive words, decide whether one such aligned typesetting has total length exactly L. | Easy3 | StringMath+1 | No attempts yet | 2s | 512 MB | Judgeable |
| Star in ParenthesesGiven balanced parentheses with one star, count the matching pairs that enclose the star's position. | Easy3 | StackString+1 | No attempts yet | 2s | 512 MB | Judgeable |
| Teenage MutantCompare each of your k trait characters against all n ancestor strings at the same position, count positions where yours differs from every ancestor, and output that count over k. | Easy3 | ArrayString+1 | No attempts yet | 2s | 512 MB | Judgeable |
| Strong PasswordGiven a string S, find the minimum number of characters to append so it has length at least 6 and contains a digit, a lowercase letter, an uppercase letter, and a special character. | Easy3 | StringGreedy+2 | No attempts yet | 2s | 512 MB | Judgeable |
| Cellphone Text CompressionFor each of N strings, output its run-length encoding: each maximal run of identical characters as a count followed by the character. | Easy3 | StringImplementation+1 | No attempts yet | 1s | 512 MB | Judgeable |
| LunGiven a card number string with one digit replaced by 'x', find the smallest digit for 'x' that makes the number pass the Luhn check. | Easy3 | ImplementationMath+2 | No attempts yet | 1s | 512 MB | Judgeable |
| Word ClockConvert an hour and minute into the words a word clock shows, using past or to and special phrases for 0, 15, 30, and 45 minutes. | Easy3 | ImplementationString+2 | No attempts yet | 0.5s | 512 MB | Judgeable |
| Integral of a PolynomialParse a degree-at-most-1 polynomial string and print its integral, writing x^2 as xx and the constant of integration as W. | Easy3 | StringImplementation+2 | No attempts yet | 1s | 256 MB | Judgeable |
| The Deeper, The BetterGiven a correct bracket string with digits inside, score each digit by the brackets enclosing it and print the highest score. | Easy3 | StackString+1 | No attempts yet | 1s | 256 MB | Judgeable |
| Only Three!Count how many length-3 windows of a digit string are strictly increasing and are not extended to a run of four or more consecutive digits. | Easy3 | StringImplementation+2 | No attempts yet | 1s | 256 MB | Judgeable |
| Typing PracticeGiven a short sentence, assign each key press (letters plus Shift and space) to the left or right hand under QWERTY rules and balance the counts, letting the left hand press one extra when the difference is one. | Easy3 | StringGreedy+1 | No attempts yet | 1s | 256 MB | Judgeable |
| Claire and PalindromeFill each '?' in a string with a lowercase letter so the whole string becomes a palindrome, printing any valid result. | Easy3 | StringTwo pointers+1 | No attempts yet | 1s | 256 MB | Judgeable |
| Circuit MathEvaluate a valid postfix boolean circuit over up to 26 variables and print T or F for the given input assignment. | Easy3 | StackString+1 | No attempts yet | 1s | 1024 MB | Judgeable |
| Beer BillParse each bill line as either an item price with optional bars or a bars-only rake line, then print the total (beer at 42) rounded up to a multiple of 10 in the N,- format. | Easy3 | ImplementationString+2 | No attempts yet | 2s | 512 MB | Judgeable |
| Strange Cipher CodeSplit a string into case-insensitive runs of equal letters, map each run to 1 if its length is at least K and 0 otherwise, and drop later runs whose letter already appeared. | Easy3 | StringImplementation+2 | No attempts yet | 1s | 1024 MB | Judgeable |
| Issuing PlatesFor each of M plates, decide whether any of N bad words appears as a substring after mapping leetspeak digits to letters. | Easy3 | StringString matching+2 | No attempts yet | 1s | 512 MB | Judgeable |
| Black and WhiteGiven an n by n grid of B and W cells, check that every row and column is balanced and has no three cells of the same color in a row. | Easy3 | ArrayImplementation+2 | No attempts yet | 1s | 512 MB | Judgeable |
| Basketball One-on-OneGiven a string recording who scored and how many points each time, determine which player won the basketball game under the eleven-point and win-by-two rules. | Easy3 | ImplementationSimulation+2 | No attempts yet | 1s | 512 MB | Judgeable |
| Soft PasswordsGiven a stored password S and an entered password P, decide whether P is accepted: equal to S, a digit-prepend/append of S, or the case-reversed form of S. | Easy3 | StringImplementation+2 | No attempts yet | 1s | 512 MB | Judgeable |
| ZOAC 2A disk holds the 26 uppercase letters in a circle, and an arrow starts at 'A'. Find the minimum total rotations needed to print a given string in order. | Easy3 | ImplementationGreedy+2 | No attempts yet | 1s | 512 MB | Judgeable |
| A Cipher in WonderlandFor the i-th line, read the sentence starting at the first character and print every i-th character in order. | Easy3 | StringImplementation | No attempts yet | 1s | 512 MB | Judgeable |
| Word ProcessorFormat N words into lines of at most K characters using the greedy first-fit rule, then print the result. | Easy3 | SimulationImplementation+2 | No attempts yet | 2s | 512 MB | Judgeable |
| SECHTDecode a string where each letter was replaced by the uppercase or lowercase form of the character to its left (or lowercase itself if the left is not a letter). | Easy3 | StringImplementation | No attempts yet | 2s | 512 MB | Judgeable |
| SENTIRead L comments, each ending with a period, and count how many contain a word from a given positive list and how many contain one from a negative list. | Easy3 | StringImplementation+1 | No attempts yet | 2s | 512 MB | Judgeable |
| New Year and NamingGiven two cyclic string sequences, return the concatenation of the pair selected by each queried year index. | Easy3 | ImplementationMath+2 | No attempts yet | 1s | 1024 MB | Judgeable |
| Time ZoneGiven a time in Beijing (UTC+8) and a target time zone string, print the corresponding 24-hour clock time. | Easy3 | ImplementationMath+2 | No attempts yet | 1s | 256 MB | Judgeable |
| Cyclic ShiftsGiven a text T and a string S, decide whether T contains any cyclic shift of S as a contiguous substring. | Easy3 | StringString matching+2 | No attempts yet | 2s | 512 MB | Judgeable |
| Palindromic FizzBuzzPrint every integer from S to E, replacing any palindromic number with the string Palindrome!. | Easy3 | ImplementationMath+2 | No attempts yet | 1s | 512 MB | Judgeable |
| DatesEach input line is a date in day.month.year or month/day/year format; print both formats, validating that the date actually exists. | Easy3 | ImplementationString+2 | No attempts yet | 1s | 512 MB | Judgeable |
| Counting WordsSplit a sentence on spaces and hyphens, then split any token that looks like a French contraction (c', j', n', m', t', s', l', d', qu' followed by a vowel) into two words, and count the total. | Easy3 | StringImplementation+2 | No attempts yet | 2s | 1024 MB | Judgeable |
| Endless StringStarting from a string A, repeatedly replace every $ in S with the previous result, then print characters from position min to max after N runs. | Medium4 | StringRecursion+2 | No attempts yet | 2s | 128 MB | Judgeable |
| Room NumberGiven digit prices and a budget, find the largest possible room number (no leading zero unless it's just 0) that can be bought within the budget. | Medium4 | GreedyString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Remote ControlGiven a target channel and a set of broken digit buttons, compute the minimum button presses to reach the channel from 100 using digits, plus and minus. | Medium4 | Brute forceString+2 | No attempts yet | 2s | 256 MB | Judgeable |
| KickdownGiven two gear strings of 1s and 2s, slide one horizontally to minimize the combined width without any overlapping position having a tooth (2) on both. | Medium4 | StringBrute force+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Make a PalindromeRearrange the letters of a given uppercase string into the lexicographically smallest palindrome, or report it is impossible. | Medium4 | StringGreedy+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Enormous Wealth 2Given two huge decimal integers n and m (up to 10^1000), compute the quotient and remainder of dividing n by m using big-integer division. | Medium4 | MathString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Lucky StringsCount the distinct rearrangements of a short string (length up to 10) that have no two adjacent equal characters. | Medium4 | BacktrackingCombinatorics+1 | No attempts yet | 2s | 256 MB | Judgeable |
| PolyominoCover every run of X cells with 2-cell (BB) and 4-cell (AAAA) blocks and print the lexicographically smallest resulting board, or -1 if some run has odd length. | Medium4 | GreedyString+2 | No attempts yet | 2s | 128 MB | Judgeable |
| Text EditorSimulate a line editor with cursor movement, character deletion, and insertion commands, printing the final string. | Medium4 | StackSimulation+2 | No attempts yet | 0.3s | 512 MB | Judgeable |
| Similar WordsCount unordered pairs of equal-length words that are related by some bijection between letters, similar to the isomorphic-strings check. | Medium4 | StringHash map+1 | No attempts yet | 2s | 128 MB | Judgeable |
| FlippingGiven a binary string, find the minimum number of contiguous-segment flips needed to make all characters equal. | Medium4 | StringGreedy+1 | No attempts yet | 2s | 128 MB | Judgeable |
| English ReadingCount how many dictionary-word combinations match each scrambled sentence when each word's middle letters can be permuted freely. | Medium4 | Hash mapString+2 | No attempts yet | 2s | 128 MB | Judgeable |
| BishopGiven board size N as a big number up to 70 digits, compute the maximum bishops placeable on an N by N board without mutual attacks, which is 2N-2 (or 1 if N=1). | Medium4 | MathString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Perfect Attendance AwardCount length-N attendance strings over O, L, A that have at most one L and no three consecutive A's, modulo 1,000,000. | Medium4 | Dynamic programmingString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Glyph DecodingCount how many length-g substrings of S are letter-for-letter rearrangements of a given word W. | Medium4 | Sliding windowString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Minsik Language Word SortingSort Minsik language words using a custom 20-letter alphabet where the digraph 'ng' counts as a single letter between 'n' and 'o'. | Medium4 | StringSorting+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Decompressed String LengthCompute the total length of a string after fully expanding nested K(Q) compression patterns, where K is a single digit repeat count. | Medium4 | StackString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| String SearchImplement KMP string matching to count and list all 1-indexed starting positions where pattern P occurs in text T of length up to 1,000,000. | Medium4 | String matchingString | No attempts yet | 2s | 256 MB | Judgeable |
| Postfix NotationConvert a fully parenthesized-or-not infix arithmetic expression with single-letter operands into its postfix notation. | Medium4 | StackString | No attempts yet | 2s | 128 MB | Judgeable |
| LCS of Three StringsCompute the length of the longest common subsequence shared by three given strings using dynamic programming. | Medium4 | Dynamic programmingString | No attempts yet | 2s | 128 MB | Judgeable |
| Chemistry 101Parse a chemical equation with molecule multipliers and element counts, then report which elements differ in count between reagents and products. | Medium4 | StringHash map+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Decode CountCount the number of ways to decode a digit string into letters A-Z, modulo 1,000,000. | Medium4 | Dynamic programmingString | No attempts yet | 2s | 128 MB | Judgeable |
| Exponential OperationPrint the exact decimal expansion of 1/2^N without trailing zeros, for N up to 250, using big-number arithmetic. | Medium4 | MathImplementation+1 | No attempts yet | 2s | 8 MB | Judgeable |
| Digital ClockGiven a broken 5x3 segment display for four digits where lit cells are always correct but some are missing, find the earliest valid hh:mm time consistent with the pattern. | Medium4 | Brute forceImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Transaction Limit CheckingParse bank customer, account, and transaction records to validate ownership and per-day, per-type transaction and exposure limits, printing a result per instruction. | Medium4 | Hash mapSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Cipher DecryptionGiven a key and ciphertext produced by a columnar transposition cipher, reconstruct the original plaintext. | Medium4 | StringSimulation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Writing Consecutive Numbers 3Given N, find the earliest 1-based index where the digit-string of N occurs inside the concatenation of integers 1 through N. | Medium4 | String matchingString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Custom Table SorterRead tables and per-line sort specifications, then output the table rows stably sorted by given field/direction keys for each specification, grouped and formatted with blank lines. | Medium4 | SortingString+1 | No attempts yet | 1s | 128 MB | Judgeable |
| String Alignment ScoreCompute the maximum scoring alignment of two strings using gap and mismatch/match scoring, which is a classic sequence alignment (edit distance style) DP. | Medium4 | Dynamic programmingString | No attempts yet | 2s | 128 MB | Judgeable |
| Chemical Formula MassParse a chemical formula with nested parentheses and digit multipliers to compute the total atomic mass using H=1, C=12, O=16. | Medium4 | StackString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Large Integer ArithmeticCompute the sum, difference, and product of two signed integers up to 1000 digits without built-in bignum support. | Medium4 | MathString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Large Number CalculationParse and evaluate an arithmetic expression with big integers up to 10^100, respecting operator precedence and floor division for negatives. | Medium4 | MathString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Hamming PathBuild a graph where binary codes connect if their Hamming distance is 1, then output a shortest path between two given codes via BFS. | Medium4 | BFSGraph+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Bracket ValueParse a bracket string with two bracket types and compute its defined nested value, or output 0 if it is invalid. | Medium4 | StackString+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Number CardsCount the ways to split a digit string into tokens each representing a valid card number from 1 to 34 (no leading zero issues implied). | Medium4 | Dynamic programmingString | No attempts yet | 1s | 128 MB | Judgeable |
| Drawing PolygonsGiven a reference closed-path digit sequence tracing a polygon, find which candidate sequences represent the same polygon allowing rotation of starting point and direction reversal but not geometric rotation or reflection. | Medium4 | String matchingString+1 | No attempts yet | 1s | 128 MB | Judgeable |
| FaxImplement run-length encoding with specific bit-packed run and literal prefix formats, splitting long runs and literal blocks according to size limits. | Medium4 | SimulationString+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Next Greater NumberGiven a large number as a digit string, find the smallest permutation of its digits that is greater than it, or report BIGGEST if none exists. | Medium4 | StringGreedy+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Chip Stack ShuffleSimulate repeated riffle shuffles of two chip stacks and find the minimum number of shuffles to reach a target stack, or report -1. | Medium4 | SimulationString | No attempts yet | 1s | 128 MB | Judgeable |
| Horizontal and Vertical PuzzleGiven 6 three-letter words, choose 3 as rows and 3 as columns so the grid's columns also match the remaining words, outputting the lexicographically smallest valid arrangement. | Medium4 | Brute forceString+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Infinite Binary Tree TraversalGiven a string of L/R/P/* moves in an infinite binary tree, sum the node values over all traversals from expanding each '*' into L, R, or P. | Medium4 | MathString+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Quiz HintsGenerate three progressive hint strings for a text answer by masking letters with dots and revealing them in stages based on rounded fractional counts. | Medium4 | StringSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Urinal Flush ScheduleSimulate a sensor log to detect when a urinal usage streak of K seconds is followed by an absence streak of L seconds, printing each flush time or NIKAD. | Medium4 | SimulationString+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Programming Language ZParse and simulate a tiny toy language with variable assignments, nested REPEAT loops, and PRINT statements, applying mod-10000 arithmetic. | Medium4 | SimulationImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| String Expansion and DistanceCompute the minimum alignment cost between two strings using edit-distance style dynamic programming with character mismatch costs and a fixed gap penalty K. | Medium4 | Dynamic programmingString | No attempts yet | 1s | 128 MB | Judgeable |
| Molecular MassParse a nested chemical formula with parentheses and repeat counts, then compute the total molecular mass from atomic weights. | Medium4 | StackRecursion+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Radio TransmissionGiven a received string that is part of a repeated broadcast, find the length of the shortest repeating unit using KMP failure function. | Medium4 | String matchingString | No attempts yet | 1s | 128 MB | Judgeable |
| The VowDetermine, for each word and up to length 50000, whether it can be split into a sequence of one or two letter chemical element symbols using DP. | Medium4 | Dynamic programmingString | No attempts yet | 1s | 128 MB | Judgeable |
| HeadshotGiven a circular string of loaded/empty chambers, decide whether shooting immediately or re-spinning gives a lower chance of firing given the previous chamber was empty. | Medium4 | StringProbability+1 | No attempts yet | 1s | 128 MB | Judgeable |
| iSharpParse a C-like multi-variable type declaration with pointer, reference, and array symbols, then print each variable on its own line with its symbols moved to the front in reversed order. | Medium4 | StringImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Access Control ListsParse an ordered ACL of allow/deny IP network rules and, for each query IP, output whether the first matching rule grants or denies access. | Medium4 | Bit manipulationString+2 | No attempts yet | 3s | 256 MB | Judgeable |
| Important WiresParse boolean formulas over up to 11 wires and count distinct output tuples across all wire assignments by brute-force enumeration. | Medium4 | StringBit manipulation+1 | No attempts yet | 3s | 256 MB | Judgeable |
| Search by templateParse a pattern with literal letters, wildcards, and allow/forbid letter groups, then find all positions where it matches inside a large text. | Medium4 | String matchingString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| CalculatorParse and evaluate fully parenthesized arithmetic expressions with big integers up to 90 digits, printing Error on overflow, negative results, or division by zero. | Medium4 | StringMath+2 | No attempts yet | 1s | 128 MB | Judgeable |