<p>Two strings, <code>X</code> and <code>Y</code>, are considered similar if either they are identical or we can make them equivalent by swapping at most two letters (in distinct positions) within the string <code>X</code>.</p>

<p>For example, <code>&quot;tars&quot;</code>&nbsp;and <code>&quot;rats&quot;</code>&nbsp;are similar (swapping at positions <code>0</code> and <code>2</code>), and <code>&quot;rats&quot;</code> and <code>&quot;arts&quot;</code> are similar, but <code>&quot;star&quot;</code> is not similar to <code>&quot;tars&quot;</code>, <code>&quot;rats&quot;</code>, or <code>&quot;arts&quot;</code>.</p>

<p>Together, these form two connected groups by similarity: <code>{&quot;tars&quot;, &quot;rats&quot;, &quot;arts&quot;}</code> and <code>{&quot;star&quot;}</code>.&nbsp; Notice that <code>&quot;tars&quot;</code> and <code>&quot;arts&quot;</code> are in the same group even though they are not similar.&nbsp; Formally, each group is such that a word is in the group if and only if it is similar to at least one other word in the group.</p>

<p>We are given a list <code>strs</code> of strings where every string in <code>strs</code> is an anagram of every other string in <code>strs</code>. How many groups are there?</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> strs = [&quot;tars&quot;,&quot;rats&quot;,&quot;arts&quot;,&quot;star&quot;]
<strong>Output:</strong> 2
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> strs = [&quot;omv&quot;,&quot;ovm&quot;]
<strong>Output:</strong> 1
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= strs.length &lt;= 300</code></li>
	<li><code>1 &lt;= strs[i].length &lt;= 300</code></li>
	<li><code>strs[i]</code> consists of lowercase letters only.</li>
	<li>All words in <code>strs</code> have the same length and are anagrams of each other.</li>
</ul>

def is_similar(str1: str, str2: str) -> bool:
    m = len(str1)
    d = 0
    for i in range(m):
        if str1[i] != str2[i]:
            d += 1
    return d <= 2

class Solution:
    def numSimilarGroups(self, strs: List[str]) -> int:
        n = len(strs)
        m = len(strs[0])
        #p = 1000000009
        #randoms = [random.randint(1, p) for i in range(m)]
        
        edges = []
        for i in range(n):
            for j in range(i + 1, n):
                if is_similar(strs[i], strs[j]):
                    edges.append((i, j))
        #hashes = []
        #for i in range(n):
        #    hashes.append(sum([randoms[j] * ord(strs[i][j]) for j in range(m)]))
        #for i in range(m):
        #    for j in range(i + 1, m):
        #        hash_dict = dict()
        #        for k in range(n):
        #            hash_k = hashes[k]
        #            hash_k -= randoms[i] * ord(strs[k][i])
        #            hash_k -= randoms[j] * ord(strs[k][j])
        #            if hash_k not in hash_dict:
        #                hash_dict[hash_k] = [k]
        #            else:
        #                hash_dict[hash_k].append(k)
        #        for prob_set in hash_dict.values():
        #            if len(prob_set) == 1:
        #                continue
        #            for k in range(len(prob_set) - 1):
        #                edges.append([prob_set[k], prob_set[k + 1]])
                #for prob_set in hash_dict.values():
                #    if len(prob_set) == 1:
                #        continue
                #    real_dict = dict()
                #    for k in prob_set:
                #        str_k = [strs[k][l] for l in range(len(strs[k])) if l != i and l != j]
                #        str_k = ''.join(str_k)
                #        if str_k not in real_dict:
                #            real_dict[str_k] = [k]
                #        else:
                #            real_dict[str_k].append(k)
                #    for real_set in real_dict.values():
                #        if len(real_set) == 1:
                #            continue
                #        for k in range(len(real_set) - 1):
                #            edges.append([real_set[k], real_set[k + 1]])

        graph = [set() for i in range(n)]
        for (i, j) in edges:
            graph[i].add(j)
            graph[j].add(i)

        visited = set()
        components = 0
        for i in range(n):
            if i in visited:
                continue
            components += 1
            to_visit = [i]
            while len(to_visit) > 0:
                current = to_visit.pop()
                if current in visited:
                    continue
                visited.add(current)
                to_visit.extend(list(graph[current]))

        return components
16700