Java/src/main/java/com/thealgorithms/strings/RemoveDuplicateFromString.java

package com.thealgorithms.strings;

/**
 * @author Varun Upadhyay (https://github.com/varunu28)
 */
public final class RemoveDuplicateFromString {
    private RemoveDuplicateFromString() {
    }

    /**
     * Removes duplicate characters from the given string.
     *
     * @param input The input string from which duplicate characters need to be removed.
     * @return A string containing only unique characters from the input, in their original order.
     */
    public static String removeDuplicate(String input) {
        if (input == null || input.isEmpty()) {
            return input;
        }

        StringBuilder uniqueChars = new StringBuilder();
        for (char c : input.toCharArray()) {
            if (uniqueChars.indexOf(String.valueOf(c)) == -1) {
                uniqueChars.append(c); // Append character if it's not already in the StringBuilder
            }
        }

        return uniqueChars.toString();
    }
}