# Questions tagged [substrings]

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### Highest covering repeated string

Let's say I have the following string: XXXXXAYYYYBYYYYCXXXXXDYYYY We can see that the substring XXXXX is 5 characters long, ...
391 views

### Number of distinct substrings

I know how to find the number of distinct substrings for a string (using suffix arrays) and I was wondering if there was a way to find this number for all of its prefixes. I already have an $O(N^2)$ ...
364 views

### Understanding the Baeza-Yates Régnier algorithm (multiple string matching, extended from Boyer-Moore)

First of all, excuse me if I write a lot, I tried to summarize my research so that everyone can understand. R. Baeza-Yates and M. Regnier published in 1993 a new algorithm for searching a two ...
71 views

### Sequence where every subset exists as some contiguous subsequence

Given a set (i.e., a collection of distinct elements), how would you find a minimal sequence where every subset of that set can be found as the elements in some contiguous subsequences? The order of ...
79 views

### What is the intuition behind the "edit sensitive parsing" tree?

If I understand right then ESP tree is defined as : given any string $x$ of finite length over an alphabet one can construct "an" ESP tree corresponding to it say $T_x$ such that each leaf of the tree ...
21 views

### Smart String search algorithm

I'm looking for a solution to search for strings in a large text file. I would like to match strings with as many of those words in close proximity as possible. For example, if a query is for the ...
59 views

### Shortest common cyclic superstring

The shortest common cyclic superstring problem is closely related to the shortest common superstring problem. The difference is that each of the strings in the input set may have an arbitrary rotation ...
37 views

### Permutation to maximise strings' common prefix

Is there a good algorithm for finding a permutation which, applied to all the strings in a set, maximises the weight of those with a common fixed length prefix. Given a set $S=\{(s,w)\}$ of pairs of ...
4k views

### Convert given string to Palindrome with given substring

Given a String S1 and String S2. Convert string S1 to a palindrome string such S2 is a substring of that palindromic string. Only operation allowed on S1 is replacement of any character with any other ...
176 views

### Counting subarrays where each number either doesn't occur or occurs odd number of times

We have given array $V$ of $N$ integers, we want to count the number of subarrays of the array such that each elements in the subarray either doesn't occur at all, or it occurs odd number of times. ...
26 views

### Has anyone seen the following string classifier discussed?

The closes related question I have found for this is Find string patterns preferably in regex for string streams, but it has no answer and is also a little less constrained as my idea. Given a set of ...
30 views

### How to find the alphabetically min and max of substrings that begin with [a, b, c, d, e] and end with [h, i, j, k, l, n]

I was asked this question today: given a very long string x, which contains only lower case alphabets. A valid substring can only started with [a, b, c, d, e] and ends with [h, i, j, k, l, n] IF we ...
91 views

### Boyer-Moore jump table

I have a pattern $P$ of length $m$, i.e. $P = p_0, p_1, \ldots, p_{m-1}$ which I want to build a simple jump table for (not considering special optimizing cases for now). I only want to build a jump ...
120 views

### finding all cyclic substrings of a string

I have been stuck on this problem for a while now; any help would be appreciated. Given a string S, find the number of distinct substrings which are composed of 2 or more consecutive strings. For ...
68 views

### Max sum of k contiguous subarrays

The question is: given an array of size $n$ and a number $m$, now our goal is to find AT MOST $m$ contiguous subarrays such that the sum of all these subarrays is the largest. It is also required that ...
38 views

### Smallest string containing sets of letters

I am looking for a solution to this problem: Given multiple sets of letters (Set0={a,b,c,d}, Set1={d,e,f,g}, Set2={a,b,e,g}, ...), what is the minimal length of the string containing all the sets. The ...
744 views

### most efficient way to compute number of anagrams of a string

This is a question from Hackerrank. Given a string S, find the number of "unordered anagrammatic pairs" of substrings. In other words, find the number of unordered pairs of substrings of S that are ...
50 views

### Why is the second while loop in KMP not a conditional statement?

When building the partial match table for KMP: ...
28 views

### Number of borders of all substrings in a string

Can you please help with solving the following problem. Given a string $s$, we need to find the number of borders of all its substrings. For a single string we can count all the borders in O(n) time ...
146 views

### Turing Machine substring

I want to create a turing machine that describes the language L={x#y | x,y\in {0,1}* and x is a substring of y}. However I'm not sure how to start writing the transition function δ as I've just gotten ...
32 views

### Best way to find and store difference between two strings

I want to implement my version of the Codeshare service. Now I'm thinking of an implementation where all users have access to one string that can change (if you already have a better option here - ...
148 views

### String Search - how to find the "most" accurate string?

Assume I have the following list of companies: Apple Big Apple Google Then I have this sample string: Big Apple is a company that is trying to be the next Google. Given the list of companies and ...
332 views

### Computing substring language on automata

Given a DFA, it is possible to compute the automaton that recognizes the language of its substrings (you can compute it as the automaton that recognizes the suffixes of its prefixes). I would like to ...
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### Why is step 4 and 5 necessary in this Cycle Cover Superstring Algorithm?

(Shortest Common Superstring: Input: A set S = {s1, . . . , sn} of strings over an alphabet Σ. Feasible solutions: Each superstring w of S, i.e., each string w that contains all strings $s_i$ ∈ S as ...