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Can you guys simplify these examples

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#1

Seriously this is suppose to be about just sliding windows and arrays and now i have to figure out what is a sliding hash?

Course: Grokking Coding Interview Patterns in Java - Learn Interactively
Lesson: Solution: Repeated DNA Sequences - Grokking Coding Interview Patterns in Java

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#2

Hello @David_ChenFitzgerald,
I am sorry for the inconvenience caused by our side. Could you please clarify what your exact concern is? Are you not satisfied with the example problem given in the lesson?

#3

Basically, the section is all about sliding windows " Solution: Repeated DNA Sequences - Grokking Coding Interview Patterns in Java". So what is a the rolling hash, how does it work, why should i use a rolling hash, it needs some better visuals or something in order to be less confusing to first timers.

#4

HI, i also have some misunderstandings in that example.

  1. I dont figure out following statement:
    image
    image970×360 12.5 KB

    How did you come to the solution like this, like using a exponents here and decrementing exp’s, i dont get it.
    and why do we use the digit 4 ? i know cos there are 4 different numbers ? but how someone could come this solution, and especially, using this 4 value with exponents
    could you please clarify these,
  2. why do we use 4 exactly and how did you come to think that you need to use 4 here ?
  3. how did you come to the solution that we need to use an exp, and decrement it ?
    if those are the just solutions, ok im agree with it, but if there are some rules, please explain it just more.
    I know youre using them to save the order of the characters, but its not just easy to think that we need a 4 or count of distinct characters and decrement the exp every time.
    Thank you
#5

I got the idea, after doing some research, this is rabin karp algorithm, and now i got the rule)
It would be better if you remind the names of algorithms, when you use them, thank you

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#6

@Akmal_Nodirov @David_ChenFitzgerald
I found it confusing because they need to use the exact algorithm name. Rolling hash is a Rabin Karp algorithm that is used for searching/matching patterns in the text using a hash function.

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