LeetCode 893 - Groups of Special-Equivalent Strings

https://leetcode.com/problems/groups-of-special-equivalent-strings/

You are given an array A of strings.

Two strings S and T are special-equivalent if after any number of moves, S == T.

A move consists of choosing two indices i and j with i % 2 == j % 2, and swapping S[i] with S[j].

Now, a group of special-equivalent strings from A is a non-empty subset S of A such that any string not in S is not special-equivalent with any string in S.

Return the number of groups of special-equivalent strings from A.

https://leetcode.com/problems/groups-of-special-equivalent-strings/discuss/163413/Java-Concise-Set-Solution

For each String, we generate it's corresponding signature, and add it to the set.
In the end, we return the size of the set.

    public int numSpecialEquivGroups(String[] A) {
        Set<String> set= new HashSet<>();
        for (String s: A){
            int[] odd= new int[26];
            int[] even= new int[26];
            for (int i=0; i<s.length(); i++){
                if (i%2==1) odd[s.charAt(i)-'a']++;
                else even[s.charAt(i)-'a']++;
            }
            String sig= Arrays.toString(odd)+Arrays.toString(even);
            set.add(sig);
        }
        return set.size();
    }

https://leetcode.com/problems/groups-of-special-equivalent-strings/discuss/163767/Straightforward-Java-solution

map1 - the distribution of counts of the characters at even positions
map2 - the distribution of counts of the characters at odd positions
set - how many unique distributions

https://leetcode.com/problems/groups-of-special-equivalent-strings/discuss/163547/Python-1-liner

    def numSpecialEquivGroups(self, A):
        return len(set("".join(sorted(s[0::2])) + "".join(sorted(s[1::2])) for s in A))