Lists: group duplicates and make new lists acc.to number of duplicates

Question

Sorry, I'm too tired to figure it out now (too long no sleep), and project deadline is in 1 hour...

I have a lists i.e. like this: {aaa,aaa,bbb,ccc,aaa,bbb,ccc,bbb}. I need to prepare myList defined this way:

List<List<String>> myList = new ArrayList<List<String>>();

to present itself like separate lists according to number of duplicates: {aaa,bbb} {ccc}

here is my ugly code:

int maxAnagramsNumber = 0;
Set<String> unique = new HashSet<String>(anagramLineList);

for (String key : unique) { //set max number of anagrams
    if (maxAnagramsNumber < Collections.frequency(anagramLineList, key)){
        maxAnagramsNumber = Collections.frequency(anagramLineList, key);
    }
}


int countedAnagrams = 0; 

for (int i=maxAnagramsNumber; i > 1; i--){ // group and make new list items acc.to number of duplicates

    for (String anagramUnit : unique){

        if(countedAnagrams != i && countedAnagrams != 0){
            anagramLineListSorted.add(anagramUnit);
        }
        countedAnagrams = i;
    }
    myList.add(anagramLineListSorted);

Answer 1

all anagrams will have the same set of characters. create a hashmap with the sorted list of chars as key and a list of the actual strings as values. Then finally combine all the values into a single list. try to think how this can be done. i can provide some code if you struggle

pass your original array of strings to this function

Code

public List<String> anagrams(String[] strs) {
    ArrayList<String> result = new ArrayList<String>();
    if(strs == null || strs.length == 0)
        return result;

    HashMap<String, ArrayList<Integer>> map = new HashMap<String, ArrayList<Integer>>();
    for(int i=0; i<strs.length; i++){
        char[] arr = strs[i].toCharArray();
        Arrays.sort(arr);
        String t = String.valueOf(arr);
        if(map.get(t) == null){
            ArrayList<Integer> l = new ArrayList<Integer>();
            l.add(i);
            map.put(t, l);
        }else{
            map.get(t).add(i);
        }
    }

    for(ArrayList<Integer> l: map.values()){
        if(l.size() > 1){
            for(Integer i: l){
                result.add(strs[i]);
            }
        }
    }

    return result;
}

if all you need is to divide the list

ArrayList<String> result = new ArrayList<String>();

for(ArrayList<String> l : combined)
    for(String g : l)
        result.add(g);

now result will have all your strings with anagrams grouped together.

Answer 2

I have not compile it (probably there are some syntax issues). But logic should work as you expect.

int maxAnagramsNumber = 0;
Set<String> unique = new HashSet<String>(anagramLineList);

Map<String, List<String>> ananas = new Map<String, List<Strin>>();

for (String ana:unique) {

    char[] chars = theWord.toCharArray();
    Arrays.sort(chars);
    String key = new String(chars);


    List<String> llist = ananas.get(key)
    if (llist == null) {
        llist = new List<String>()
        ananas.put(key, llist)
    } 
    llist.add(ana)
    }

    println(ananas);