What's a permuted index?

This is a discussion on What's a permuted index? within the C++ Programming forums, part of the General Programming Boards category; So in my book, its giving me this problem..but I have no idea what its asking me to do. I ...

  1. #1
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    What's a permuted index?

    So in my book, its giving me this problem..but I have no idea what its asking me to do. I cant figure out what a permuted index is doing.

    Code:
    5-1. Design and implement a program to produce a permuted index. A permuted index is one in which each phrase is indexed by every word in the phrase. So, 
    given the following input,
    The quick brown fox
    jumped over the fence
    
    the output would be
    
        The quick     brown fox
    jumped over the     fence
     The quick brown     fox
                        jumped over the fence
            jumped       over the fence
               The        quick brown fox
      jumped over         the fence
                      The quick brown fox
    I copied this to the best of my ability. I tried to google it but I could not find any sites that thoroughly explained it. Might be one or two spaces off, but any help would be appreciated =D

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    So it's an index (as in the thing at the back of a book), it looks like, but every word in the phrase is used as a search term. So the first phrase is indexed under "brown", "fox", "quick", and "The" and the second by "fence", "jumped", "over", and "the".

    I'm not sure what you're getting at in terms of the output.

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    Hm...I sadly still don't get it...That output was what was given me in the book. I simply tried to duplicate it. I am however off by a few spaces I bet.

  4. #4
    Crazy Fool Perspective's Avatar
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    Given any prefix of the line, you need an index entry to get the rest of the line.

    Sentence
    A1 A2 A3 A4 A5

    Index
    : A1 A2 A3 A4 A5
    A1 : A2 A3 A4 A5
    A1 A2 : A3 A4 A5
    A1 A2 A3 : A4 A5
    A1 A2 A3 A4 : A5


    Your example looks funny because the entries are not in order, but they're all there. I'm not sure how they'd want you to distinguish between the beginning of different phrases though.

  5. #5
    Hail to the king, baby. Akkernight's Avatar
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    That's from Accelerated C++ It's exactly like that if I remember, I never really figured it out, just close then I just moved on since it was so frusterating, my brain startet sweating xP
    Currently research OpenGL

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