Leetcode Easy

Problem

You are given an array A of strings.

A move onto S consists of swapping any two even indexed characters of S, or any two odd indexed characters of S.

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

For example, S = "zzxy" and T = "xyzz" are special-equivalent because we may make the moves "zzxy" -> "xzzy" -> "xyzz" that swap S[0] and S[2], then S[1] and S[3].

Now, a group of special-equivalent strings from A is a non-empty subset of A such that:

1. Every pair of strings in the group are special equivalent, and;
2. The group is the largest size possible (ie., there isn’t a string S not in the group such that S is special equivalent to every string in the group)

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

Example 1:

Input: ["abcd","cdab","cbad","xyzz","zzxy","zzyx"]
Output: 3
Explanation:
One group is ["abcd", "cdab", "cbad"], since they are all pairwise special equivalent, and none of the other strings are all pairwise special equivalent to these.

The other two groups are ["xyzz", "zzxy"] and ["zzyx"].  Note that in particular, "zzxy" is not special equivalent to "zzyx".


Example 2:

Input: ["abc","acb","bac","bca","cab","cba"]
Output: 3


Note:

• 1 <= A.length <= 1000
• 1 <= A[i].length <= 20
• All A[i] have the same length.
• All A[i] consist of only lowercase letters.

Solution

class Solution {
public int numSpecialEquivGroups(String[] A) {
HashSet<String> uniqueBitmaps = new HashSet<>();

// Loop through all of the given words
for (String str : A) {

// Create array representations of the letters and their frequency
int[] newOddBitmap = new int['z' - 'a' + 1];
int[] newEvenBitmap = new int['z' - 'a' + 1];

// Loop through each char in the string to add it's frequency to the respectivearray
for (int i = 0; i < str.length(); i++) {
char c = str.charAt(i);
if (i % 2 == 1) {
newOddBitmap[c - 'a']++;
} else {
newEvenBitmap[c - 'a']++;
}
}

// Convert the arrays to a string because java will compare
// addresses of arrays to determine uniqueness, NOT value