class FirstUniqueCharFinder {
 
  static char find(String word) {
    int len = word.length();
    char firstUniqueChar = 0;
 
    for (int i = 0; i < len; i++) {
      char currentChar = word.charAt(i);
      String after = word.substring(i + 1, len);
      if (!after.contains(Character.toString(currentChar))) {
        firstUniqueChar = currentChar;
        break;
      }
    }
 
    return firstUniqueChar;
  }
 
  public static void main(String[] args) {
    System.out.println(find("transaction"));
    System.out.println(find("reverse"));
  }
}

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