Anagrams finding in java

Question

I stuck on a problem. I have a String array which is consist of String[]={"eat", "tea", "tan", "ate", "nat", "bat"} Now, I should segregated those word which have same letter on it and make a group. eat,tea,ate they have same letter in each word so this is a group. Group 2 should be tan,nat and Group3 should be bat. So I have to make a list of list to store those groups.

My approach:

To solve this problem I first find out the ascii values of each letter and then add those ascii values for a word. Like eat find out the ascii values of e,a,t and add them. I take this approach because if the letters are repeated in the words then they must have same ascii sum. After that I group them same Ascii sums and find out which words have those sums then they belongs to same group.

My progress I find out ascii sums and put them in a hashmap. But then I could not group the same values. As I failed to group the ascii values I cannot find out the words.I have no clue how to proceed.

I also follow this posts

post1 post2

But there approach and my approach is not same. Also the questions are different from mine. I am discussing here about a different approach which is depend upon ASCII values.

My code:

public List<List<String>> groupAnagrams(String[] strs) {
    ArrayList<Character>indivistr=new ArrayList<>();
    ArrayList<Integer>dup=new ArrayList<>();
    HashMap<Integer,Integer>mappingvalues=new HashMap<>();
    for(int i=0;i<strs.length;i++){
        int len=strs[i].length();
        int sum=0;
        for(int j=0;j<len;j++){
            indivistr.add(strs[i].charAt(j));
            int ascii=(int)strs[i].charAt(j);
            sum=sum+ascii;

        }
        mappingvalues.put(i,sum);

    }

}

One more approach I transfer the map keys in a Arraylist and map values in a ArrayList. Something like that,

ArrayList<Integer>key_con=new ArrayList< (mappingvalues.keySet()); ArrayList<Integer>val_con=new ArrayList<>(mappingvalues.values());

Then using two loops and put the same values into another list.

for(int k=0;k<val_con.size();k++){
        for(int k1=k+1;k1<val_con.size();k1++){
            if(val_con.get(k).equals(val_con.get(k1))){
                dup.add(val_con.get(k1));
            }
        }

Now if I print dup output will be [314, 314, 314, 323] which is partially correct. It should be 314,314,314,323,323,311

Answer 1

Based on the asci approach I have made a working code

public static void main(String[] args) {
        String[] values ={"eat", "tea", "tan", "ate", "nat", "bat"};
        Map<Integer, List<String>> resultMap = new HashMap<Integer, List<String>>();
        for (String value : values) {
            char[] caharacters = value.toLowerCase().toCharArray();
            int asciSum = 0;
            for (char character : caharacters) {
                asciSum = asciSum + (int)character;
            }
            System.out.println(asciSum);
            if(resultMap.containsKey(asciSum)) {
                resultMap.get(asciSum).add(value);
            }else {
                List<String> list = new ArrayList<String>();
                list.add(value);
                resultMap.put(asciSum, list);
            }
        }
        System.out.println(resultMap);
    }

This will give result

{323=[tan, nat], 311=[bat], 314=[eat, tea, ate]}

but if we encounter diff characters with same asci value sum like 10+11 = 20+1 below code will work where based on the sorted string we make the result map

public static void main(String[] args) {
        String[] values ={"eat", "tea", "tan", "ate", "nat", "bat"};
        Map<String, List<String>> resultMap = new HashMap<String, List<String>>();
        for (String value : values) {
            char[] caharacters = value.toLowerCase().toCharArray();
            Arrays.sort(caharacters);
            String sortedValue = new String(caharacters);
            System.out.println(sortedValue);
            if(resultMap.containsKey(sortedValue)) {
                resultMap.get(sortedValue).add(value);
            }else {
                List<String> list = new ArrayList<String>();
                list.add(value);
                resultMap.put(sortedValue, list);
            }
        }
        System.out.println(resultMap);
    }

This will return

{aet=[eat, tea, ate], abt=[bat], ant=[tan, nat]}

I have fixed the comments and edits provided.