839. Similar String Groups

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# 題目敘述

Two strings X and Y are similar if we can swap two letters (in different positions) of X , so that it equals Y . Also two strings X and Y are similar if they are equal.

For example, "tars" and "rats" are similar (swapping at positions 0 and 2 ), and "rats" and "arts" are similar, but "star" is not similar to "tars" , "rats" , or "arts" .

Together, these form two connected groups by similarity: {"tars", "rats", "arts"} and {"star"} . Notice that "tars" and "arts" are in the same group even though they are not similar. 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.

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

# Example 1:

Input: strs = ["tars","rats","arts","star"]
Output: 2

# Example 2:

Input: strs = ["omv","ovm"]
Output: 1

# 解題思路

# Solution