// computes the hash function of a given string. Assumes
        // that the string consists of lower case letters, upper case letters, and 
        // digits. Views the string as a base-32 number and returns equivalent
        // decimal value modulo 32. Uses bit shifting for multiplying
        // by 32 and Horner's rule for reducing number of multiplications
        private int hash(String word)
        {
                int hashValue = 0;
                for(int i = 0; i < word.length(); i++)
                // Solution for Quiz 7a:
                // Also note that we are now bit-shifting by 2 to the 6th or 64.
                        {
                                if((word.charAt(i) >= '0') && (word.charAt(i) <= '9'))
                                        hashValue = ((hashValue << 6) + (word.charAt(i) - '0') + 1) % M;
                                        // Note: this will map the values from 1 - 10
                                else
                                if((word.charAt(i) >= 'A') && (word.charAt(i) <= 'Z'))
                                        hashValue = ((hashValue << 6) + (word.charAt(i) - 'A') + 11) % M;
                                        // Note: this will map the values from 11 - 36
                                else
                                if((word.charAt(i) >= 'a') && (word.charAt(i) <= 'z'))
                                        hashValue = ((hashValue << 6) + (word.charAt(i) - 'a') + 37) % M;
                                        // Note: this will map the values from 37 - 62

                        }

                return hashValue;
        }