class Solution {

    public int maxProduct(String[] words) {

        int[] checker = new int[words.length];

        if (words == null || words.length == 0) {

            return 0;

        }

        int res = 0;

        for (int i = 0; i < words.length; i++) {

            String word = words[i];

            for (int j = 0; j < word.length(); j++) {

                char curChar = word.charAt(j);

                checker[i] |= 1 << curChar - 'a';

            }

        }

        for (int i = 0; i < words.length - 1; i++) {

            for (int j = i + 1; j < words.length; j++) {

                if ((checker[i] & checker[j]) == 0) {

                    res = Math.max(res, words[i].length() * words[j].length());

                }

            }

        }

        return res;

    }

}

public class Solution {

  public int largestProduct(String[] dict) {

    // Write your solution here

    Arrays.sort(dict, new Comparator<String>(){

      @Override

      public int compare(String a, String b) {

        return b.length() - a.length();

      }

    });

    int[] arr = new int[dict.length];

    for (int i = 0; i < dict.length; i++) {

      for (int j = 0; j < dict[i].length(); j++) {

        arr[i] |= 1 << dict[i].charAt(j) - 'a';

      }

    }

    int res = 0;

    for (int i = 1; i < dict.length; i++) {

      for (int j = 0; j < i; j++) {

        if (dict[i].length() * dict[j].length() <= res) {

          break;

        }

        if ((arr[i] & arr[j]) == 0) {

          res = dict[i].length() * dict[j].length();

        }

      }

    }

    return res;

  }

}