How to find repeated characters in a string in java

How do I find a repeated character in a string?

Given a string, find the first repeated character in it.

Following are detailed steps.

  1. Copy the given array to an auxiliary array temp[].
  2. Sort the temp array using a O(N log N) time sorting algorithm.
  3. Scan the input array from left to right. For every element, count its occurrences in temp[] using binary search.

How do you find duplicates in a string in Java?


  1. STEP 1: START.
  2. STEP 2: DEFINE String string = “Big black bug bit a big black dog on his big black nose”
  3. STEP 3: DEFINE count.
  4. STEP 4: CONVERT string into lower-case.
  5. STEP 5: INITIALIZE words[] to SPLIT the string.
  6. STEP 6: PRINT “Duplicate words in a given string:”
  7. STEP 7: SET i=0. …
  8. STEP 8: SET count =1.

How do you find non repeated characters in a string?

A Simple Solution is to run two loops. Start traversing from left side. For every character, check if it repeats or not. If the character doesn’t repeat, increment count of non-repeating characters.

How do I find a character in a string in Java?

You can search for a particular letter in a string using the indexOf() method of the String class. This method which returns a position index of a word within the string if found. Otherwise it returns -1.

How do you reverse words in a string?

Example: Program to reverse every word in a String using methods. In this Program, we first split the given string into substrings using split() method. The substrings are stored in an String array words . The program then reverse each word of the substring using a reverse for loop.

See also:  How to compare ints in java

How do you find unique characters in a string?

Using the toCharArray() method

The toCharArray() method of the String class converts the given String into an array of characters and returns it. Convert it into an array of characters. Compare each character in the array with the required one. In case of a /match the String contains the required character.

How do you remove duplicates in a sentence in Java?

“The first second was alright but the second second was tough.”;

  1. str = new LinkedHashSet<String>( Arrays. asList(str. split(“\s+”)) ). toString(). replaceAll(“[\[\],]”, “”);
  2. System. out. println(“String after removing duplicate words: “);
  3. System. out. println(str);

How do you remove duplicate characters from a string in Java?

Java program to delete duplicate characters from a given String

  1. Convert it into a character array.
  2. Try to insert elements of the above-created array into a hash set using add method.
  3. If the addition is successful this method returns true.
  4. Since Set doesn’t allow duplicate elements this method returns 0 when you try to insert duplicate elements.
  5. Print those elements.

How do you find duplicate characters in a string in Java without using collections?


  1. Create a HashMap and character of String will be inserted as key and its count as value.
  2. If Hashamap already contains char,increase its count by 1, else put char in HashMap.
  3. If value of Char is more than 1, that means it is duplicate character in that String.

How do I remove duplicate characters in a string?

There are three main ways to remove duplicates characters from String in Java; First to sort the character array of string and then remove duplicate characters in linear time. Second, use an auxiliary data structure like Set to keep track of characters already seen and then recreate String from Set.

See also:  How to create a button in java

What is charAt () in Java?

Java String charAt() Method

The charAt() method returns the character at the specified index in a string. The index of the first character is 0, the second character is 1, and so on.

Leave a Comment

Your email address will not be published. Required fields are marked *