import java.util.*;
public class WordChecker
{

    private ArrayList<String> wordList;
    public WordChecker(String[] words)
    {
        wordList = new ArrayList<String>();
        for (String word: words)
            wordList.add(word);
    }

    /**
     * Returns true if each element of wordList (except the first) contains the previous
     * element as a substring and returns false otherwise, as described in part (a)
     * Precondition: wordList contains at least two elements.
     * Postcondition: wordList is unchanged. */
    public boolean isWordChain()
    { 
        /* to be implemented in part (a) */ 

        return false; // remove this to test your answer to part a
    }

    /**
     * Returns an ArrayList<String> based on strings from wordList that start
     * with target, as described in part (b). Each element of the returned ArrayList has had
     * the initial occurrence of target removed.
     * Postconditions: wordList is unchanged.
     * Items appear in the returned list in the same order as they appear in wordList. */
    public ArrayList<String> createList(String target) 
    { 
        /* to be implemented in part (b) */ 
        return null; // remove this to test your answer to part (b)
    }
    // There may be instance variables, constructors, and methods that are not shown. }
    public static void main(String[] args)
    {
        String[] trueExample = {"an", "band", "band", "abandon"};
        String[] falseExample = {"to", "too", "stool","tools"};
        WordChecker ex1 = new WordChecker(trueExample);
        WordChecker ex2 = new WordChecker(falseExample);

        System.out.println("part (a)");
        System.out.println("Your ex1.isWordChain() returns " + ex1.isWordChain() + " <should be true>" );
        System.out.println("Your ex2.isWordChain() returns " + ex2.isWordChain() + " <should be false>" );

        System.out.println("part (b)");
        String[] partb = {"catch", "bobcat", "catchacat", "cat", "at"};
        WordChecker ex3 = new WordChecker(partb);
        System.out.println( ex3.toString() );
        
        System.out.println("createList(\"cat\") returns "+ ex3.createList("cat") +
             " <should be [ch, chacat, ] >");
        
        System.out.println("createList(\"catch\") returns "+ ex3.createList("catch") +
            " <should be [, acat] >");
        
        System.out.println("createList(\"dog\") returns "+ ex3.createList("dog") +
            " <should be [] >");
        
    }

    public String toString()
    {
        return wordList.toString();
    }
}