code: public static <E> double max(Counter<E> c) {
      double max = Double.NEGATIVE_INFINITY;
      for (double v : c.values()) {
        max = Math.max(max, v);
      }
      return max;
    }
docs: Returns the value of the maximum entry in this counter. This is also the
  Linfinity norm. An empty counter is given a max value of
  Double.NEGATIVE_INFINITY.
  
  @param c
  The Counter to find the max of
  @return The maximum value of the Counter