public class assignment6 {
    static String[] ref;
    static String input;
    static int strindex = 0;
    static int substringlength = 1;

    public static boolean isConcatenated(int n,int m){
        int index = 0;
        int i;
        boolean memo[] = new boolean[ref.length];
        for(i = 0; i < ref.length ; i++){
            if(input.substring(n,m).equals(ref[i])){
                System.out.println("input: " + input.substring(n,m) + " ref: " + ref[i]);
                memo[i] = true;
                if(n < input.length()){
                    return isConcatenated(n+1,m);
                }
            }
        }
        if(memo[i-1] == false){
            if(n == input.length())
                return false;
            else{
                if(m < input.length())
                    return isConcatenated(n,m+1);
            }
        }

        for(int j = 0; i < memo.length-1; i++){
            memo[0] = memo[i]||memo[i+1];
        }
        return memo[0];
    }

    public static void main(String[]args){

        ref = new String[]{"a","ab","abc","ba"};
        input = "abab";
        System.out.println(isConcatenated(strindex,substringlength));
    }
}