no. of comparisons in linear/binary search

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  1. #1
    Registered User alice's Avatar
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    no. of comparisons in linear/binary search

    hi, what is the no. of comparison in a worst case unsorted one-dimensional array of size N with linear search?

    is it 'N'?

    and if worst case sorted one-dimensional array of size N with binary search,

    is it (log N / log2) ?

    but what is best case in binary search?

  2. #2
    Registered User CompiledMonkey's Avatar
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    Quote Originally Posted by alice
    hi, what is the no. of comparison in a worst case unsorted one-dimensional array of size N with linear search?

    is it 'N'?

    and if worst case sorted one-dimensional array of size N with binary search,

    is it (log N / log2) ?

    but what is best case in binary search?
    I dunno if I'm right, but I'll try.

    worst case for linear search: n
    worst case binary search: log n
    best case binary search: 1 (assuming it found the result on the first attempt)

  3. #3
    Im a Capricorn vsriharsha's Avatar
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    Well, just to add a small element....
    You refer to the order by the Big O notation.
    Order for Linear Search is: O(n)
    and order for Binary Search is: O(log n).

    Cheers,
    Harsha.
    Help everyone you can

  4. #4
    & the hat of GPL slaying Thantos's Avatar
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    Worse case is log n / log 2 rounded up to the next whole integer.

    So: 8,000,000 elements would require at most 23 searches.

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    Registered User CompiledMonkey's Avatar
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    Quote Originally Posted by vsriharsha
    Well, just to add a small element....
    You refer to the order by the Big O notation.
    Order for Linear Search is: O(n)
    and order for Binary Search is: O(log n).

    Cheers,
    Harsha.
    I thought that was a given.

  6. #6
    Registered User alice's Avatar
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    then what is
    Worst case unsorted two-dimensional array of size N with linear search &
    Best case unsorted two -dimensional array of size N with linear search?

    I think the first one is log(NxN) / log 2 ?
    but what is the second one? I haven't any idea.

    or can someone told me where can I find more information(URL)?

    thk a lot.
    Last edited by alice; 06-05-2004 at 10:46 PM.

  7. #7
    Registered User CompiledMonkey's Avatar
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    Wouldn't the array be setup in such a way that you're only searching one of the two columns? Even if you did have to look at each column, I imagine you're looking at O(2n). I'm not sure about that though. Best case could be O(1) in any search.

  8. #8
    & the hat of GPL slaying Thantos's Avatar
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    Quote Originally Posted by alice
    Worst case unsorted two-dimensional array of size N with linear search &
    Best case unsorted two -dimensional array of size N with linear search?
    Worse case for unsorted arrays is always the number of elements, since the only way to search an unsorted array is by linear search.

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