import java.util.List;

public class Fold {
  
  
  public int foldl(Operator op, Integer init, List<Integer> list) {
    
    if (list.isEmpty()) 
      return init;
  
    int akk = init;
    int length = list.size();
    for (int i = 0; i < length; i++) {
     
      akk = op.operate(akk, list.get(i));
      
    }
    
    return akk;
    
  }
  
  
  public int foldr(Operator op, Integer init, List<Integer> list) {
   
    if (list.isEmpty())
      return init;
    
    int akk = init;
    int length = list.size();
    
    for (int i = length; i >= 0; i--) {
      
      akk = op.operate(list.get(i), akk);
      
    }
    
    return akk;
    
  }
  
  
}