Quickest way of storing and accessing Strings in an array

Question

I know I could go through a for loop like this (see code) and i could also add to the array in the same fashion but is there a quicker way. I don't want to use any other java API as i want to practice array's. Would using a hash function allow me to store my variables quicker and then find a certain word quicker?

edit: The problem is when using 10,000+ words the delay increases larger than 1ms

Thanks :)

int count = 0;
for(int i = 0; i < array.length; i++)
    if(array[i].equals(word)) 
        count++;

score 1 · Answer 1 · answered Nov 19 '14 at 16:29

1

You can use a 2 dimensional array :

Array [Alphabet] [Words starting with that alphabet]

answered Nov 19 '14 at 16:29

Sarthak Mittal

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This is a very simplified version of a hash map. The hash function of using the first letter is not a very good one, but if you can't use a hash map directly, it's not that bad. – Michael Myers Nov 19 '14 at 16:34
Adding to a 2d array would increase the time because i would need two for loops right? – Kingsta1993 Nov 19 '14 at 16:36
yes you are right, but the guy wanted to use and practice arrays only, so i replied with that answer :) – Sarthak Mittal Nov 19 '14 at 16:37
@MichaelMyers how could i create a simplified version of a hash map for this? Could you point me in the right direction please – Kingsta1993 Nov 19 '14 at 16:37
@kingsta: no dude you just check the first alphabet of the word and directly access the array starting with those words – Sarthak Mittal Nov 19 '14 at 16:39
@Kingsta1993: A hash map first uses some function to calculate a hash value of each item, then stores the item in a "bucket" based on the hash value. That's what this answer suggests: the hash function is simply the first letter of the word, then the bucket is the array corresponding to that letter. – Michael Myers Nov 19 '14 at 16:46
let me give you a better insight suppose your array is something like : array[26][] now whenever you encounter a word, fetch its first alphabets ascii value, if it is <=90 add 32 in it and then subtract 97, this will take care of both small and capital alphabets and access the array was i clear? – Sarthak Mittal Nov 19 '14 at 16:47
Note that this works best if you disallow non-English letters. If one of your words, is, say, [Åland](https://en.wikipedia.org/wiki/%C3%85land_Islands), you'll have problems. Or you could just make a 27th bucket for such words. – Michael Myers Nov 19 '14 at 16:52
@Michael: Yes there would be a lot of cases to consider if we start using non-English letters :) – Sarthak Mittal Nov 20 '14 at 07:05

score 1 · Answer 2 · answered Nov 19 '14 at 16:30

1

You could pre-sort the array and then use a binary-chop search on it. This would only be useful if you are looking for many words.

If you allow other structures then you can usually achieve O(1) lookup times.

answered Nov 19 '14 at 16:30

OldCurmudgeon

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score 0 · Answer 3 · answered Nov 19 '14 at 16:29

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Whenever your processing 10,000 words you can expect some delays. Depending on what word is set to you might be able to filter a bit better but as far as your code shows that's the best way to do it.

answered Nov 19 '14 at 16:29

JGerulskis

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Quickest way of storing and accessing Strings in an array

3 Answers3