Questions tagged [substrings]

Questions about algorithms related to substrings, or about properties of substrings.

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10
votes
2answers
4k views

Fast k mismatch string matching algorithm

I am looking for a fast k-mismatch string matching algorithm. Given a pattern string P of length m, and a text string T of length n, I need a fast (linear time) algorithm to find all positions where P ...
6
votes
4answers
2k views

Algorithm Request: “Shortest non-existing substring over given alphabet”

I'm looking for an (efficient) algorithm to solve the following problem: Given a string $S$ and a set of characters $M$, find the shortest string composed only of characters in $M$ that is not ...
7
votes
2answers
2k views

Automaton for substring matching

Given $s$ as a string over some alphabet, what is the best known algorithm to compute a corresponding deterministic finite-state automaton (DFA) that accepts any string that contains $s$? I am mostly ...
3
votes
2answers
2k views

Dynamic programming table for finding similar substrings is too large

Substring Diff Given two strings of length $n$, $P = p_1\dots p_n$ and $Q = q_1 \dots q_n$, we define $M(i, j, L)$ as the number of mismatches between $p_i \dots p_{i+L-1}$ and $q_j \dots q_{j+L-1}...
5
votes
1answer
694 views

Finding the smallest string that contains a given set of substrings

The algorithm I am looking for has the following requirements: Input is a set of strings. You are looking for a string containing all input strings. The resulting string should be as short as possible....
3
votes
2answers
768 views

Which is the proper algorithm to figure repeated substrings of longest total length?

Given a string $S$ and a substring $T$, define the value of $T$ to be the total length (in characters) of all non-overlapping instances of $T$ in $S$. In other words, the value of $T$ is the length ...
4
votes
1answer
6k views

Number of distinct substrings in a string

From what I have come to understand, the best way to implement it is to use the suffix array $S$ of the string $w$ and its LCP-array (Longest Common Prefix) $L$. The answer can be obtained by $$ \...
0
votes
1answer
158 views

A little help with regular expressions [duplicate]

I am trying to create a regular expression that will generate the following language under the {a,b,c} alphabet: all words that do not contain the substring "bbc" I am having a really hard time ...