Anagram Program in Java with Code and Example

In this post, we will write java programs to check whether two strings are anagram or not. We will discuss 5 different methods to check for anagram strings. Before moving ahead with Anagram program in java , first we need to know what does anagram mean?

What is Anagram ?

If two strings contain same set of characters but in different order then the two strings are called anagrams.

for example :

1. "now" and "own" 

2. "ton" and "not"

3. "fiber" and "brief"

Read Also :   5 ways of  String Concatenation in Java with Example  

Now we know what does anagram mean. Let understand the question by writing example.

Input : "now","own"
Output : true

Input : "ton" , "not"
Output : true

Input : "hello" , "he"
Output : false

Pseudo Code for Anagram Program in java using sort() and equals() method:

1. Convert the two strings into uppercase and remove all white spaces.
2. Convert the two strings into char arrays using toCharArray().
3. Sort the two character arrays using sort() method of java.util.Arrays class.
4. After sorting,  we compare both the arrays using equals() method.

import java.util.*;
import java.io.*;
public class Anagram
{
    public static void main (String[] args) throws java.lang.Exception
    {
        boolean result = isAnagram("now","own");
        System.out.println(result);
    }
    public static boolean isAnagram(String first, String second)
    {
        // remove all whitespaces and convert strings to lowercase
        first  = first.replaceAll("\\s", "").toLowerCase();
        second = second.replaceAll("\\s", "").toLowerCase();

        /* check whether string lengths are equal or not,
        if unequal then not anagram */
        if (first.length() != second.length())
        return false;

        // convert string to char array
        char[] firstArray = first.toCharArray();
        char[] secondArray = second.toCharArray();

        // sort both the arrays
        Arrays.sort(firstArray);
        Arrays.sort(secondArray);

        // checking whether both strings are equal or not
        return Arrays.equals(firstArray,secondArray);
    }
}

Pseudo Code for Anagram Program in java using Iterative method:

1. In this method we go on checking whether each character of first string is present in second string.
2. If the character is present in second string, we remove the character from the second string, and proceed to the next character of first string.
3. If any character of first string is not present in second string, we break the loop and result would be first string is not anagram of second string.

import java.util.*;
import java.lang.*;
import java.io.*;

public class Anagram
{

 public static void main (String[] args) throws java.lang.Exception
 {
  boolean result = isAnagram("now","own");
  System.out.println(result);
 }
 public static boolean isAnagram(String first, String second)
 {
  // remove all whitespaces and convert strings to lowercase
  first  = first.replaceAll("\\s", "").toLowerCase();
  second = second.replaceAll("\\s", "").toLowerCase();

  /* check whether string lengths are equal or not, 
     if unequal then not anagram */
  if (first.length() != second.length())
   return false;

  // convert first string to char array
  char[] firstArray = first.toCharArray();

  // check whether each character of firstArray is present in second string
  for (char c : firstArray)
  {
   int index = second.indexOf(c);

   // indexOf function returns -1 if the character is not found 
   if (index == -1)
    return false;

   // if character is present in second string, remove that character from second string
   second  = second.substring(0,index) + second.substring(index+1, second.length());
  }
  return true;
 }
}

Pseudo Code for Anagram Program in java using HashMap method:

1. Create one HashMap object with character as key and character occurrences as value.
2. If the character is present in first string , we increment  character  count by 1.
3. If the character is present in second string , we decrement character count by 1.
4. Iterate through HashMap ,  check the count of each character in the map , if count is not equal to 0 then return false.

import java.util.*;
import java.io.*;
public class Anagram
{
    public static void main (String[] args) throws java.lang.Exception
    {
         isAnagram("now","own");
    }
    public    static void isAnagram(String stringOne, String stringTwo) {
        //Remove all white space & case differences
        String strCopyOne = stringOne.replaceAll("\\s", "").toUpperCase();
        String strCopyTwo = stringTwo.replaceAll("\\s", "").toUpperCase();
        //If the strings aren’t the same length, not anagrams
        if (strCopyOne.length() != strCopyTwo.length()) {
            System.out.println(stringOne + " and " + stringTwo + " are not anagrams.");
            return;
        }
        //HashMap to store the number of characters
        HashMap mapOne = createMapKeys(strCopyOne);
        HashMap mapTwo = createMapKeys(strCopyTwo);
        if (mapOne.equals(mapTwo)) {
            System.out.println(stringOne + " and " + stringTwo + " are anagrams");
            } else {
            System.out.println(stringOne + " and " + stringTwo + " are not anagrams.");
        }
    }
    public static HashMap createMapKeys(String str) {
        HashMap map = new HashMap();
        for (int i = 0; i < str.length(); i++) {
            if (map.containsKey(str.charAt(i))) {
                int count = (int) map.get(str.charAt(i));
                map.put(str.charAt(i), count + 1);
                } else {
                map.put(str.charAt(i), 0);
            }
        }
        return map;
    }
}

please mention in the comments, if you have any other way to code anagram program in java.