class Solution {
  /**
   * Checks for a String represented as a SLList whether this String is a palindrome.
   * This is done by using a stack.
   *
   * An empty String or null should return true.
   *
   * @param list
   *     SLList used to represent a String
   * @return true if the String represented as a SLList is a palindrome, otherwise false
   */
  public static boolean checkPalindrome(SLList list) {
    if (list == null || list.size() == 0){
      return true;
    }
    LibraryStack<Character> stack = new LibraryStack<>();
    int n = 0;
    if (list.size() % 2 == 0){
      n = list.size()/2;
    }
    if (list.size() % 1 == 0){
      n = (list.size() + 1)/2 ;
    }
    int counter = 0;
    while (counter != n){
      stack.push(list.removeFirst());
      counter++;
    }

    while(!stack.isEmpty()){
      if (stack.pop().equals(list.removeFirst())){
        return true;
      }
    }
    return false;
  }
}