CODEWITHSUNDEEP
javasortingdictionaryhashmapselection-sort
Taylor Swift
Taylor Swift

Reputation: 242

How to sort a LinkedHashMap by value without Collections.sort()?

I'm trying to write a selection sort method for a LinkedHashMap/ArrayList but I'm having issues and I'm not sure what's wrong. It compiles but doesn't actually sort the list. I'm trying to sort in descending order by value. Any help would be appreciated.

public static List sort(LinkedHashMap<String, Integer> words) {


        List<Map.Entry<String, Integer>> entries = new ArrayList<>(words.size());
        entries.addAll(words.entrySet());

        int max;

        for(int i = 0; i < entries.size(); i++) {

            max = entries.get(i).getValue();

            for(int j = i + 1; j < entries.size(); j++) {

                if (entries.get(j).getValue().compareTo(entries.get(max).getValue()) > 0) {

                    max = entries.get(j).getValue();
                }

            }

            if(max != i) {

                Map.Entry temp1 = entries.get(i);

                entries.set(entries.get(i).getValue(), entries.get(max));

                entries.set(entries.get(max).getValue(), temp1);
            }

        }

        return entries;
    }

Upvotes: 0

Views: 98

Answers (1)

RaffleBuffle
RaffleBuffle

Reputation: 5455

You're code is essentially correct, you've just mixed up values and indices in a few places.

You need to replace:

max = entries.get(i).getValue();

with

max = i;

This

max = entries.get(j).getValue();

with 

max = j;

And

entries.set(entries.get(i).getValue(), entries.get(max));
entries.set(entries.get(max).getValue(), temp1);

with

entries.set(i, entries.get(max));
entries.set(max, temp1);

Make you sure you understand why the changes work.

Upvotes: 3

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