Java Finding Elements in Array

Question

I have five arrays where I store incoming int numbers like:

int array1 = {1,6,..}
int array2 = {2,7,..}
.
.
int array5 = {5,10,..}

Now, what I have to do, search for next numbers in another arrays.

Like,

for(i = 0, i < array1.size ; i++){

int element = array1[0] ;

//here array2, array3, ..., array5 can have different size
search for array2 to find element+1
search for array3 to find element+2
.
.
search for array5 to find element+5
}

What I am doing right now is:

Run for loop for 0 to array2 size, to find element+1 (so for others)

However, it is quite slow. Can anybody give me some idea, how to make it faster (I can change array to any-other data-structure also).

Sorry, I make two mistakes while asking, what I should mention:

1) Arrays are sorted (incremental elements always).
2) Array elements are very few (2-3) so Binary Search will be expensive.
3) I have to perform the search for thousand times means when channel input pause, I have to perform search, then again channel start and I have to perform search ... so on.

Do your numbers always increment by a fixed amount (5 in the given example)? — Rory Hunter
– Rory Hunter, Commented Apr 17, 2012 at 15:45
Use for (int i=0, ...) in your for loops, otherwise be aware your i variable can be changed somewhere else in your method. — Ozzy
– Ozzy, Commented Apr 17, 2012 at 15:47
@Ozzy, no I do that. My codes o/P is correct. No issue with that. I want faster one. — Arpssss
– Arpssss, Commented Apr 17, 2012 at 15:48
You could try putting the values of array2, array3, etc into HashSet<Integer>, and then simply call set2.contains(element); — Greg Case
– Greg Case, Commented Apr 17, 2012 at 16:00

evanwong · Accepted Answer · 2012-04-17 15:47:03Z

4

If the arrays are sorted, use binary search to find the element instead of looping thru it for every single element.

answered Apr 17, 2012 at 15:47

evanwong

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2 Comments

Arpssss Over a year ago

your answer is correct. But, I forgot to mention something. I modified my question.

Louis Wasserman Over a year ago

If the array size is always very small, then the linear search you're already doing is the best way to do it.

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