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Questions tagged [longest-common-substring]

23 questions
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2 answers

Longest common substring in linear time

We know that the longest common substring of two strings can be found in $\mathcal O(N^2)$ time complexity. Can a solution be found in only linear time?
user99043
7
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1 answer

Find longest common substring using a rolling hash

The longest common substring (LCS) of two input strings $s,t$ is a common substring (in both of them) of maximum length. We can relax the constraints to generalize the problem: find a common substring of length $k$. We can then use binary search to…
mrk
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Does the Longest Common Subsequence problem reduce to its binary version?

I am working on a problem regarding the Longest Common Subsequence (LCS) of two strings, and I was wondering if there is any reduction from the general case of LCS to its binary version, i.e. by solving LCS for bit-strings we can also solve LCS with…
Nima
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3
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Intellij string search and highlight algorithm

I'm searching for an alogrithm that takes two strings, a query and a string that is to be searched for the query. The algorithm should result in a 'found' when the string contains the characters of the query in the right order but with any amount of…
Philip Müller
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2
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1 answer

Probabilistic Substring Match

I'm looking for an algorithm that will help me determine substring matches at scale. I have a pool of 100+ million "needles" (strings). I can do as much pre-processing on them as I want, and storage is cheap. On detection side, I have both a very…
Scovetta
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1 answer

How to find longest recurring pattern from lage string data set?

I need to find the substring that is from a 100,000 characters this substring must be most repeated and it need to be longest substring for…
Nuwan Indika
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Efficiently find longest common substring for all substring pairs of S and T

I am trying to find the Gesalt similarity of a string $S$ and all substrings of $T$ using Gestalt Pattern Matching (Ratcliff Obershelp Algorithm) This algorithm requires me to find the matches of S and T which is defined as follows $$ matches(S,T) =…
Daigo
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Get count of longest zigzag sub-sequences

I know how to get longest zigzag sub-sequence and length of it. There are several methods available for that. But some times there are many sub-sequences available which have same length. How to obtain that?
Lakindu Akash
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1 answer

Longest common subsequence with at most one swap

Is there a good algorithm for calculating the longest common subsequence where we consider two sequences identical if they can be transformed to one another with at most 1 swapping of subsequences (i.e. taking two non-overlapping subsequences of the…
Nesa
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Which algorithm to use to find all common substring (LCS case) with really big strings

I'm looking for a particular case of longest common substring (LCS) problem. In my case I have two really big strings (tens or hundreds of milions byte characters) and need to find the LCS and other long strings. A simplified example $S_0$ =…
Ivan
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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 strings as for example: Foo 25 bar zoo…
Gunther Schadow
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Longest palindrome after swapping operation

I know that Manacher's algorithm can be used to find the longest palindromic substring of a string in linear time. But I want to find the longest palindromic substring after swapping any two indices once. If I run a for loop twice in $O(n^2)$ to…
Sharingan
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Longest Common subsequence theorem in CLRS

In CLRS in the dynamic programming chapter, there is a theorem about the longest common subsequence prefix that states the following: Theorem Let the $X=(x_1,x_2,\dots,x_m)$ and $Y=(y_1,y_2,\dots,y_n)$ be sequences, and let $Z…
markeb
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1 answer

Can I find all the common subsequences between 2 sequences by using dynamic programming?

I need to know if there's a dynamic programming algorithm that returns all common subsequences between 2 sequences not just the longest one. Thank you.
user118909
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Longest common sequence matrix giving wrong answer

I am trying to find longest common sequence for these two strings SHINCHAN NOHARAAA The common sequence is NHA of length 3 But when I am trying to find out this through LCS matrix which I learnt from this link…
Pawan Nogariya
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