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upper_bound in Java for binary search
By jaswanthi, history, 9 years ago, In English

I couldn't find upper_bound equivalent in java. Is there any alternative function that I can use ?

PS: I did google this

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9 years ago, # |
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You can write your own upper_bound and lower_bound (It's not hard), and there is another alternative (using a TreeSet)

Here are some methods :

ceiling(E e) : Returns the least element in this set greater than or equal to the given element, or null if there is no such element.

floor(E e) : Returns the greatest element in this set less than or equal to the given element, or null if there is no such element.

headSet(E toElement) : Returns a view of the portion of this set whose elements are strictly less than toElement.

You can find the full documentation here : https://docs.oracle.com/javase/7/docs/api/java/util/TreeSet.html

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9 years ago, # |
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Java has Arrays.binary_search() static method instead.

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    9 years ago, # ^ |
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    But it is not useful in that case. If there are more than one element present in the array it will return any index.

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      9 years ago, # ^ |
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      Create array of pairs (a[i], i). Then use binarySearch(new Pair(x, -1)) or binarySearch(new Pair(x, n))

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        9 years ago, # ^ |
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        Yes it can be done in that way but using object array results in taking far more time in sorting than primitive array.

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9 years ago, # |
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http://scod.ir/Yit

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