Method getHash

49. Group Anagrams/Solution.cpp:40–50

    }

    unsigned long getHash(string str) {
        int cnt[26] = {0};
        for (char c : str) {
            cnt[c - 'a'] ++ ;
        }
        unsigned long res = 0;
        for (int i = 0; i < 26; i++) {
            res += cnt[i] * pow(prime, i);
        }
        return res;
    }


    // O(1)