public List<String> fullJustify(String[] words, int L) {
        List<String> list = new ArrayList<String>();
        int sta=0;
        int length =0;
        for(int i=0 ; i < words.length && words[i] != "";i++){
            length += words[i].length() + 1;
            //   System.out.println(length);
            if(length-1 >L ){
                line(Arrays.copyOfRange(words, sta, i),length-2 - words[i].length(),L ,list);
                sta = i;
                i--;
                length =0;
            }
        }
        if(sta < words.length){
            String str ="";
            length = 0;
            for(int i=sta; i< words.length &&  words[i] != "";i++){
                str += words[i] + " ";
                length += words[i].length()+1;
            }
            for(int i=0; i< L - length;i++)
                str += " ";

            list.add(str.substring(0,L));
        }


        return list;
    }