Checking Anagram of a String array input

问题

This is my code below to check anagram of a given string array.
It always gives me false even in the simplest case with only one input.
I don't understand am I not converting string array into string correctly or my algorithm is plain wrong.

public class anagram
{
     static boolean isAnagram(String[] s1, String[] s2) { 
        String str = s1.toString();
        String str2 = s2.toString();
        if (str.length() != str2.length()) 
            return false;

        for (int i =0; i<str.length();i++)
        { 
            for (int j = 0;j<str2.length();j++)
            { 
                if (s1[i] == s2[j]) {
                    return true; 
                }
                return false; 
            }                   
        } 
        return true; 
    }

    public static void main(String [] args){
        String [] s1 = {"shot"};
        String [] s2 = {"host"};
        System.out.println(isAnagram(s1,s2));
    }
}

Can you please help me identify what is wrong?

回答1:

Your algorithm for checking seems to be a little incorrect.
Edited the isAnagram function here:

public static void main(String[] args)
{
    String s1 = "shotaabb";
    String s2 = "hostbaba";
    System.out.printf("String s1: %s, String s2: %s%n", s1, s2);
    System.out.println(isAnagram(s1, s2) ?
            "Is anagram" : "Is not an anagram");
}

static boolean isAnagram(String s1, String s2)
{
    String str1 = new String(s1);
    String str2 = new String(s2);

    // Ensures that both strings are of the same length
    if (str1.length() != str2.length())
        return false;

    int str1Len = str1.length();
    for (int i = 0; i < str1Len; i++)
    {
        int charIndex = str2.indexOf(str1.charAt(i));

        if(charIndex == -1) // Not found in str2
            return false;
        else
        {
            // Remove the character from str2
            str2 = str2.substring(0, charIndex) +
                str2.substring(charIndex + 1);
        }
    }

    return true;
}

What the code does is:

Gets a character from s1, finds the index of that character inside s2
If the index is -1, character not found inside s2, return false
If the character can be found inside s2, remove it from s2
At the end, if all characters inside s1 can be found in s2, return true
Based on the fact that both strings are of the same length, if all character in s1 can be found & removed from s2, s1 is an anagram of s2 & vice versa.

Output:

String s1: shotaabb, String s2: hostbaba
Is anagram

Update (Comparing String arrays):

String[] strArr1 = {"shot", "dcba"};
String[] strArr2 = {"host", "abcd"};

for(String s1 : strArr1)
{
    for(String s2 : strArr2)
    {
        System.out.printf("%nString s1: %s, String s2: %s%n", s1, s2);
        System.out.println(isAnagram(s1, s2) ?
            "Is anagram" : "Is not an anagram");
    }
}

Output for updated code:

String s1: shot, String s2: host
Is anagram

String s1: shot, String s2: abcd
Is not an anagram

String s1: dcba, String s2: host
Is not an anagram

String s1: dcba, String s2: abcd
Is anagram

回答2:

Strings are not primitive variables in Java, therefore you must use the .equals() method instead of checking for equality using '==' to perform a thorough comparison.

回答3:

public static bool IsAnagram(string firstString, string secondString)
{
    firstString = firstString.Replace(" ", "").ToLower();
    secondString = secondString.Replace(" ", "").ToLower();

    var firstStringArray = firstString.OrderBy(x => x);
    var secondStringArray = secondString.OrderBy(x => x);

    string s1 = new string(firstStringArray.ToArray());
    string s2 = new string(secondStringArray.ToArray());

    if (s1.Equals(s2))
    {
        return true;
    } else {
        return false;
    }          
}

回答4:

To check if two String are anagram, case not sensitive, here the method:

public boolean isAnagram(String s1, String s2) {
    class SortChars{
        String sort(String source) {
            char[] chars = source.toLowerCase().toCharArray();
            Arrays.sort(chars);
            return new String(chars);
        }
    }
    SortChars sc = new SortChars();
    return sc.sort(s1).equals(sc.sort(s2));
}

The solution is taken from the book "cracking the coding interview", Authored by Gayle Laakmann McDowell

来源：https://stackoverflow.com/questions/27393141/checking-anagram-of-a-string-array-input

标签

java

arrays

string

anagram