Group Anagrams in Java: Explanation & Practice

Problem summary

Given an array of strings, group anagrams together. Anagrams are words with same characters rearranged.

Starter code

public class Main {
    public static void main(String[] args) {
        String[] strs = {"eat", "tea", "tan", "ate", "nat", "bat"};
        
        // Key insight: sorted anagram = same string
        // Use HashMap<sorted_string, list_of_anagrams>
        // Print each group on new line
    }
}

Expected output and test cases

• Group by sorted form

  ate eat tea
  nat tan
  bat

• [] → empty

• [a] → just a

  a

Hints

1. Two anagrams, when sorted, become the same string
2. Use sorted string as HashMap key
3. Value is list of all strings that sort to that key
4. Alternative: use character count array as key

Related Data Structures & Algorithms exercises

• Practice Maximum Subarray (Kadane's Algorithm) in Java
• Practice Two Sum (Unsorted) in Java
• Practice Subarray Sum Equals K in Java

Practice all Data Structures & Algorithms exercises · Run this idea in the Java compiler