Custom hashtable with distibuted values

Question

I have some integer value like:

0, 2, 3, 1021, 2001, 2101, 3054 ...

Now, I want to put those values in a hash table. The integers are distributed like: every 1000 interval [means, 0-1000, 1000-2000 ...] has maximum 2-3 values.

Now, in my hash table I'm simply setting the bucket number with load factor 0.5. And hash code is simply: Integer % bucket number. However, it gives many collision.

Is there any better way to handle this type of particular distribution?

I have many files with such integers. So, setting fixed bucket number is impossible.

Why not use a standard HashMap? Does it give you as many collisions? — assylias, Aug 03 '13 at 08:50
@assylias, it's slow and I could not handle it in my own way. — user1838343, Aug 03 '13 at 08:52
Setting a fixed bucket number is what happens when you completely ignore the number of buckets. The number of buckets increases if it isn't sufficient. — tbodt, Aug 03 '13 at 08:52
If standard hashmap is not an option, you might need to write your own implementation — Tala, Aug 03 '13 at 08:52
@tbodt, true. sorry, I forgot to mention, I know how many numbers are going to be inserted from the file size. — user1838343, Aug 03 '13 at 08:55

score 0 · Answer 1 · edited May 23 '17 at 12:11

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@asslysis is saying you have to create a your own hashing function GoodHashingFunction Good Hashing Function is necessary because if it is any duplicate key it will replace value. See the code

import java.util.Hashtable;
public class HashMapKey {
public static void main(String[] args) {
    Hashtable a=new Hashtable();
    a.put("abc", 1000);
    a.put("abc", -1000);
    a.put("cde", 2000);
    System.out.println(a);
}

}

and output be {abc=-1000, cde=2000}

edited May 23 '17 at 12:11

Community

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answered Aug 03 '13 at 09:34

Sheel

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@user1838343 I think it will be ok you can also modify your load factor you can find useful link here [Hashfunction](http://en.wikipedia.org/wiki/Hash_function) – Sheel Aug 03 '13 at 09:39
@user1838343if you are still n trouble then comment. – Sheel Aug 03 '13 at 09:52

Custom hashtable with distibuted values

1 Answers1