package test5;

import java.util.List;

public class Test5E 
{
    /**
     * Returns the maximum of the digits of the given string.
     * 
     * @param digits a string consisting of only digits.
     * @pre. digits.length() > 0 && digits consists of only digits.
     * @return the maximum of the digits of the given string.
     */
    public static int max(String digits)
    {
	int max;
	if (digits.length() == 1)
	{
	    max = digits.charAt(0) - '0';
	}
	else
	{
	    max = Math.max(digits.charAt(0) - '0', Test5E.max(digits.substring(1)));
	}
	return max;
    }
    
    
    /**
     * Returns the length of the concatenation of the strings of the given list.
     * For example, for the list ["this", "is", "the", "last", "test"] the
     * length is 17. 
     * 
     * @param sentence a list of strings.
     * @pre. sentence != null
     * @return the length of the concatenation of the strings of the given list.
     */
    public static int length(List<String> sentence)
    {
	return Test5E.length(sentence, 0);
    }
    
    /**
     * Returns the length of the concatenation of the strings of the 
     * sub list of the given list starting at the given begin index.
     * For example, for the list ["this", "is", "the", "last", "test"] 
     * and the begin index 2, the length is 11. 
     * 
     * @param sentence a list of strings.
     * @pre. sentence != null
     * @param begin the begin index of the sub list
     * @pre. begin >= 0 && begin <= list.size()
     * @return he length of the concatenation of the strings of the 
     * sub list of the given list starting at the given begin index.
     */
    public static int length(List<String> sentence, int begin)
    {
	int length;
	if (begin == sentence.size())
	{
	    length = 0;
	}
	else
	{
	    length = sentence.get(begin).length() + Test5E.length(sentence, begin + 1);
	}
	return length;
    }
}