docs: public List<Double> std(List<Double> mean) {
      List<Double> result = new ArrayList<>(mean.size());
      result.addAll(this.variance(mean));
      for (int i = 0; i < result.size(); i++)
        result.set(i,Math.sqrt(result.get(i)));
  
      return result;
    }
  
    public void mark(int index) {
      this.marks.set(index, MAX_LENGHT);
    }
  
    public boolean isUnMarked(int index) {
      return this.marks.get(index) == 0;
    }
  
    public void decreaseMark(int index) {
      if (this.marks.get(index) > 0)
        this.marks.set(index,this.marks.get(index)-1);
    }
  
    public Double getMaxObjective(int index) {
      Double result = Double.NEGATIVE_INFINITY;
  
      for (List<Double> list : this.history)
        result = Math.max(result, list.get(index));
  
      return result;
    }
  }