Strings and text

Parsing, matching, and tries

Under construction

Still being built. Things may change

Total results3,614 problems

Impartial Strings
Hard9
String matching, Math
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Gasoline Prices
Hard9
Tree, Union-find+1
No attempts yet
Time limit
3.5s
Memory limit
1024 MB
Judgeable
Double Palindrome
Hard9
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Substring in a Substring
Hard9
String matching, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Popcount Words
Hard9
String matching, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hardcore String Counting
Hard9
String matching, Dynamic programming+1
No attempts yet
Time limit
8s
Memory limit
2048 MB
Judgeable
StrCartesian
Hard9
String, Trie+2
No attempts yet
Time limit
13s
Memory limit
2048 MB
Judgeable
Generator
Hard10
Implementation, String+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
String Palindrome Queries
Hard10
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Robots
Hard10
Implementation, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Creation
Hard10
Geometry, String matching+2
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Horses
Hard10
Graph, String+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
HQ0-9+-INCOMPUTABLE?!
Hard10
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Beautiful Automata
Hard10
Graph, Topological sort+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Impartial StringsFor each case, decide whether a finite automaton can generate exactly the strings where S and T occur equally often as substrings.	Hard9	String matchingMath	No attempts yet	4s	1024 MB	Judgeable
Gasoline PricesGiven a tree with a price range per station, count valid price assignments after each year's pair of path constraints forces matching prices along both paths.	Hard9	TreeUnion-find+1	No attempts yet	3.5s	1024 MB	Judgeable
Double PalindromeCounts substrings of s that split into two equal-length halves, where each half is a palindrome, with n up to 500000.	Hard9	StringString matching+1	No attempts yet	2s	1024 MB	Judgeable
Substring in a SubstringFor each query, count how many times the substring s[l1..r1] occurs inside the substring t[l2..r2] of two given strings.	Hard9	String matchingBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Popcount WordsEach interval contributes the parity of popcount over its range, the parts are concatenated, and each query counts how often its 0/1 pattern appears in the result.	Hard9	String matchingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Hardcore String CountingCount strings of length m over 26 letters where s first appears as a substring at the very end, modulo 998244353, with n up to 1e5 and m up to 1e9.	Hard9	String matchingDynamic programming+1	No attempts yet	8s	2048 MB	Judgeable
StrCartesianGiven string sets A and B, sort all concatenations a_i + b_j lexicographically and report the (i, j) pair at each queried position k.	Hard9	StringTrie+2	No attempts yet	13s	2048 MB	Judgeable
GeneratorRead an index 0 to 10 and output the exact contents of the matching recovered file gen_i.out from the archive.	Hard10	ImplementationString+2	No attempts yet	2s	256 MB	Judgeable
String Palindrome QueriesMaintain a lowercase string under block moves, reversals, and single-character insertions, answering after each change whether a given substring reads the same forwards and backwards.	Hard10	StringString matching+1	No attempts yet	2s	256 MB	Judgeable
RobotsDesign two robots' instruction tables so they classify a binary string as fine or coarse from its middle third's A and B counts, using four-bit memories, exact-then-wildcard dispatch, and 1000n steps.	Hard10	ImplementationBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
The CreationGiven N named points, weight Voronoi neighbor links by shared substring length, then answer minimum-path queries while parent links change.	Hard10	GeometryString matching+2	No attempts yet	8s	1024 MB	Judgeable
HorsesGiven a commutation graph of horse kinds and a queue a, list the lexicographically ordered minimal queues b that commute with a, printing each as a polynomial hash modulo 998244353.	Hard10	GraphString+1	No attempts yet	2s	256 MB	Judgeable
HQ0-9+-INCOMPUTABLE?!Construct an HQ0-9+-INCOMPUTABLE?! program of at most 10000 commands whose final buffer equals a given target string.	Hard10	StringSimulation+2	No attempts yet	1s	1024 MB	Judgeable
Beautiful AutomataGiven a DAG, find the lexicographically smallest string whose suffix automaton is exactly this graph, or report -1 if none exists.	Hard10	GraphTopological sort+2	No attempts yet	2s	512 MB	Judgeable