Java Array, Finding Duplicates

Question

I have an array, and am looking for duplicates.

duplicates = false;
for(j = 0; j < zipcodeList.length; j++){
    for(k = 0; k < zipcodeList.length; k++         


        

Answer 1

You can use bitmap for better performance with large array.

    java.util.Arrays.fill(bitmap, false);

    for (int item : zipcodeList)
        if (!bitmap[item]) bitmap[item] = true;
        else break;

UPDATE: This is a very negligent answer of mine back in the day, keeping it here just for reference. You should refer to andersoj's excellent answer.