How to find Duplicate characters in given String in Java?
Problem Description :
Write a program in Java that prints all duplicate characters in a String. For example "Java" has one duplicate character 'a'.
Algorithm :
- Convert original String to character Array.
- Remove all duplicate characters from String by converting String to Set.
- Get new String by converting Set (from Step 2) to String.
- Convert String (from Step 3) to character Array.
- If original String and new String are same then there is no duplicate character in original String otherwise go to Step 6.
- One by one check all characters of new String with Original String. If count > 1 it means duplicate characters present in String.
Java Program :
Output :
Case 1 :
 |
| Output - Duplicate characters present in given String. |
Case 2 :
 |
| Output - Duplicate characters not present in given String. |
References :
https://www.tutorialspoint.com/java/java_hashset_class.htm
https://www.tutorialspoint.com/java/java_linkedhashset_class.htm
https://www.tutorialspoint.com/java/java_strings.htm
https://www.tutorialspoint.com/java/java_using_iterator.htm
Thank you friends, I hope you have clearly understood the solution of this problem. If you have any doubt, suggestion or query please feel free to comment below. You can also discuss this solution in our forum.
Tags : Interview questions on String, Solution in Java, Duplicate characters, Iterator, HashSet, LinkedHashSet, for loop, while loop, if statement, char[] array, String functions.
About Author:
I am simple guy with lot of ambitions. My main motive is to share whatever knowledge I have related to programming. With me you can easily learn how to solve any programming problem in Java.You can connect with me on social networking sites also.
Let's Get Connected: Linkedin | Facebook | Google Plus
How to find Duplicate characters in given String in Java?
Reviewed by Rohit Agarwal
on
10/23/2016
Rating:
Reviewed by Rohit Agarwal
on
10/23/2016
Rating:
Hello Rohit,
ReplyDeleteCan't we solve this problem in little simpler and short way.
Because we have to just count the number of characters that are repeated.
Can't we do it just using HashMap().
If we then the solution will become very small and easy to understand.
May be I am wrong. Please update me on this
Hi Piyush,
DeleteWe have to print duplicate characters in String. Yes, we can do this problem using HashMap() but I don't think so that is short and simple because we have to perform following steps.
1) Break string into characters.
2) Found the count corresponding to each character -> To achieve this we need nested loop.
3) Take character as a Key and character count as a value, then store it into HashMap().
4) In HashMap() check for which Key , Value is greater than 1 and finally print Keys.
If you have any better approach to solve this problem using HashMap() please share with us. I will be more happy to see your approach :)
Hello Rohit
DeleteI think we can solve this problem using following steps,
HashMap map,
Count=0,
for i=0, i<length(string), i++
{
Chari=string.charat(i),
If(map.haskey(chari))
Count++
Else
Map.add(chari,0),
}
I don't know the exact function name but I think we can do it in this manner.
DeletePlease response..
Thank you.
Nice article String Programs in Java
ReplyDeletethanks.
Thank you Anurag.
DeleteRohit bhai appke hashset article mere interview clear me kaam aaya. Sir ji aapka bahut thanks.
ReplyDeleteCheers,
http://www.flowerbrackets.com/hashset-java/