Algorithm for grouping anagram words

Question

Given a set of words, we need to find the anagram words and display each category alone using the best algorithm.

input:

man car kile arc none like
<         


        

Answer 1

In C, I just implemented the following hash which basically does a 26-bit bitmask on whether the word in the dictionary has a particular letter in it. So, all anagrams have the same hash. The hash doesn't take into account repeated letters, so there will be some additional overloading, but it still manages to be faster than my perl implementation.

#define BUCKETS 49999

struct bucket {
    char *word;
    struct bucket *next;
};

static struct bucket hash_table[BUCKETS];

static unsigned int hash_word(char *word)
{
    char *p = word;
    unsigned int hash = 0;

    while (*p) {
        if (*p < 97 || *p > 122) {
            return 0;
        }
        hash |= 2 << (*p - 97);
        *p++;
    }

    return hash % BUCKETS;
}

Overloaded buckets created and added as linked list, etc. Then just write a function that makes sure that the words that match the hash value are the same length and that the letters in each are 1 to 1 and return that as a match.