Optimizing Jaro-Winkler algorithm

Question

I have this code for Jaro-Winkler algorithm taken from this website. I need to run 150,000 times to get distance between differences. It takes a long time, as I run on an Androi

Answer 1

Instead returning the common characters using GetCommonCharacters method, use a couple of arrays to keep the matches, similarly to the C version here https://github.com/miguelvps/c/blob/master/jarowinkler.c

/*Calculate matching characters*/
for (i = 0; i < al; i++) {
    for (j = max(i - range, 0), l = min(i + range + 1, sl); j < l; j++) {
        if (a[i] == s[j] && !sflags[j]) {
            sflags[j] = 1;
            aflags[i] = 1;
            m++;
            break;
        }
    }
}

Another optimization is to pre-calculate a bitmask for each string. Using that, check if the current character on the first string is present on the second. This can be done using efficient bitwise operations.

This will skip calculating the max/min and looping for missing characters.