Code Destine

Problem Statement

You have given an array of strings, write a program to group all the anagrams.

Note :- Strings consists of only lowercase English letters.

Example 

Input :- ["eat", "tea", "tan", "ate", "nat", "bat"]
Output :-
[
  ["ate","eat","tea"],
  ["nat","tan"],
  ["bat"]
]

Input :- ["abcd", "bcad", "eaft", "tfea", "abc", "def"],
Output :-
[
  ["abc"],
  ["def"],
  ["abcd", "bcad"],
  ["eaft", "tfea"]
]

Solution

This problem can be solved in following steps :-

1. Create the HashMap object of type String as a Key and List of Strings as a value.
2. Traverse the input list of strings from start to end and for each String S, convert it into a character array.
3. Sort the character array created in the last step and convert it into a string.
4. Put the sorted string as a key and List of Strings (after adding String S) as a value into the HashMap.
5. Return the list of values of HashMap as a result.

Program

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Main {

	public static void main(String[] args) {		
		Main main = new Main();
		String[] anagrams = new String[] {"abcd", "bcad", "eaft", "tfea", "abc", "def"};
		List<List<String>> result = main.groupAnagrams(anagrams);
		for(List<String> list : result) {
			for(String str : list) {
				System.out.print(str + ", ");
			}
			System.out.println();
		}
	}
	
	/* Solution */
	public List<List<String>> groupAnagrams(String[] strs) {
        
        String temp;
        char[] array;
        List<String> list;
        Map<String, List<String>> map = new HashMap<>();
        for(String str: strs){
            
            array = str.toCharArray();
            Arrays.sort(array);
            temp = String.valueOf(array);
            
            if(map.containsKey(temp)){
                map.get(temp).add(str);
            }else {
                list = new ArrayList<>();
                list.add(str);
                map.put(temp, list);
            }
            
        }
        
        List<List<String>> result = new ArrayList<>();
        for(List<String> value: map.values()){
            result.add(value);
        }
        return result;        
    }
}

Result

abc, 
def, 
abcd, bcad, 
eaft, tfea, 

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