Java Program To Check Whether Two Strings Are Anagram Of Each Other - GeeksforGeeks

23 Dec, 2021
Write a function to check whether two given strings are anagram of each other or not. An anagram of a string is another string that contains the same characters, only the order of characters can be different. For example, “abcd” and “dabc” are an anagram of each other.
Method 1 (Use Sorting):
Sort both stringsCompare the sorted strings
Sort both strings
Compare the sorted strings
Below is the implementation of the above idea:
Java
// Java program to check whether two strings// are anagrams of each otherimport java.io.*;import java.util.Arrays;import java.util.Collections;class GFG{    /* Function to check whether two strings       are anagram of each other */    static boolean areAnagram(char[] str1,                              char[] str2)    {        // Get lengths of both strings        int n1 = str1.length;        int n2 = str2.length;         // If length of both strings is not        // same, then they cannot be anagram        if (n1 != n2)            return false;         // Sort both strings        Arrays.sort(str1);        Arrays.sort(str2);         // Compare sorted strings        for (int i = 0; i < n1; i++)            if (str1[i] != str2[i])                return false;         return true;    }     // Driver Code    public static void main(String args[])    {        char str1[] = {'t', 'e', 's', 't'};        char str2[] = {'t', 't', 'e', 'w'};               // Function Call        if (areAnagram(str1, str2))            System.out.println(            "The two strings are" +            " anagram of each other");        else            System.out.println(            "The two strings are not" +            " anagram of each other");    }}// This code is contributed by Nikita Tiwari.
 Output:
The two strings are not anagram of each other
Time Complexity: O(nLogn)
Method 2 (Count characters): This method assumes that the set of possible characters in both strings is small. In the following implementation, it is assumed that the characters are stored using 8 bit and there can be 256 possible characters. 
Create count arrays of size 256 for both strings. Initialize all values in count arrays as 0.Iterate through every character of both strings and increment the count of character in the corresponding count arrays.Compare count arrays. If both count arrays are same, then return true.
Create count arrays of size 256 for both strings. Initialize all values in count arrays as 0.
Iterate through every character of both strings and increment the count of character in the corresponding count arrays.
Compare count arrays. If both count arrays are same, then return true.
Below is the implementation of the above idea:
Java
// Java program to check if two strings// are anagrams of each otherimport java.io.*;import java.util.*;class GFG{    static int NO_OF_CHARS = 256;     /* Function to check whether two strings       are anagram of each other */    static boolean areAnagram(char str1[],                              char str2[])    {        // Create 2 count arrays and initialize        // all values as 0        int count1[] = new int[NO_OF_CHARS];        Arrays.fill(count1, 0);        int count2[] = new int[NO_OF_CHARS];        Arrays.fill(count2, 0);        int i;         // For each character in input strings,        // increment count in the corresponding        // count array        for (i = 0; i < str1.length &&             i < str2.length; i++)        {            count1[str1[i]]++;            count2[str2[i]]++;        }         // If both strings are of different length.        // Removing this condition will make the        // program fail for strings like "aaca"        // and "aca"        if (str1.length != str2.length)            return false;         // Compare count arrays        for (i = 0; i < NO_OF_CHARS; i++)            if (count1[i] != count2[i])                return false;         return true;    }     // Driver code    public static void main(String args[])    {        char str1[] =        ("geeksforgeeks").toCharArray();        char str2[] =        ("forgeeksgeeks").toCharArray();         // Function call        if (areAnagram(str1, str2))            System.out.println(            "The two strings are" +            "anagram of each other");        else            System.out.println(            "The two strings are not" +            " anagram of each other");    }}// This code is contributed by Nikita Tiwari.
 Output:
The two strings are anagram of each other
Method 3 (count characters using one array): The above implementation can be further to use only one count array instead of two. We can increment the value in count array for characters in str1 and decrement for characters in str2. Finally, if all count values are 0, then the two strings are anagram of each other. Thanks to Ace for suggesting this optimization. 
Java
// Java program to check if two strings// are anagrams of each otherclass GFG{ static int NO_OF_CHARS = 256; // Function to check if two strings// are anagrams of each otherstatic boolean areAnagram(char[] str1,                          char[] str2){      // Create a count array and initialize    // all values as 0    int[] count = new int[NO_OF_CHARS];    int i;     // For each character in input strings,    // increment count in the corresponding    // count array    for(i = 0; i < str1.length; i++)    {        count[str1[i] - 'a']++;        count[str2[i] - 'a']--;    }     // If both strings are of different    // length. Removing this condition    // will make the program fail for    // strings like "aaca" and "aca"    if (str1.length != str2.length)        return false;     // See if there is any non-zero    // value in count array    for(i = 0; i < NO_OF_CHARS; i++)        if (count[i] != 0)        {            return false;        }    return true;} // Driver codepublic static void main(String[] args){    char str1[] =    "geeksforgeeks".toCharArray();    char str2[] =    "forgeeksgeeks".toCharArray();     // Function call    if (areAnagram(str1, str2))        System.out.print(        "The two strings are " +        "anagram of each other");    else        System.out.print(        "The two strings are " +        "not anagram of each other");}}// This code is contributed by mark_85
Output:
The two strings are anagram of each other
Time Complexity: O(n)Please refer complete article on Check whether two strings are anagram of each other for more details!
anikakapoor
Amazon
anagram
Goldman Sachs
Nagarro
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Amazon
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Nagarro
Strings
anagram
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