<p>You are given a string <code>s</code>, and an array of pairs of indices in the string&nbsp;<code>pairs</code>&nbsp;where&nbsp;<code>pairs[i] =&nbsp;[a, b]</code>&nbsp;indicates 2 indices(0-indexed) of the string.</p>

<p>You can&nbsp;swap the characters at any pair of indices in the given&nbsp;<code>pairs</code>&nbsp;<strong>any number of times</strong>.</p>

<p>Return the&nbsp;lexicographically smallest string that <code>s</code>&nbsp;can be changed to after using the swaps.</p>

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

<pre>
<strong>Input:</strong> s = &quot;dcab&quot;, pairs = [[0,3],[1,2]]
<strong>Output:</strong> &quot;bacd&quot;
<strong>Explaination:</strong> 
Swap s[0] and s[3], s = &quot;bcad&quot;
Swap s[1] and s[2], s = &quot;bacd&quot;
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;dcab&quot;, pairs = [[0,3],[1,2],[0,2]]
<strong>Output:</strong> &quot;abcd&quot;
<strong>Explaination: </strong>
Swap s[0] and s[3], s = &quot;bcad&quot;
Swap s[0] and s[2], s = &quot;acbd&quot;
Swap s[1] and s[2], s = &quot;abcd&quot;</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;cba&quot;, pairs = [[0,1],[1,2]]
<strong>Output:</strong> &quot;abc&quot;
<strong>Explaination: </strong>
Swap s[0] and s[1], s = &quot;bca&quot;
Swap s[1] and s[2], s = &quot;bac&quot;
Swap s[0] and s[1], s = &quot;abc&quot;
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10^5</code></li>
	<li><code>0 &lt;= pairs.length &lt;= 10^5</code></li>
	<li><code>0 &lt;= pairs[i][0], pairs[i][1] &lt;&nbsp;s.length</code></li>
	<li><code>s</code>&nbsp;only contains lower case English letters.</li>
</ul>

class Solution:
    def smallestStringWithSwaps(self, s: str, pairs: List[List[int]]) -> str:
        swaplists = []
        seen = {}
        len_swaplists = 0
        
        for pair in pairs:
            # print(pair, seen, swaplists)
            if pair[0] not in seen and pair[1] not in seen:
                swaplists.append(set(pair))
                seen[pair[0]] = len_swaplists
                seen[pair[1]] = len_swaplists
                len_swaplists += 1
            elif pair[0] not in seen:
                idx = seen[pair[1]]
                swaplists[idx].add(pair[0])
                seen[pair[0]] = idx
            elif pair[1] not in seen:
                idx = seen[pair[0]]
                swaplists[idx].add(pair[1])
                seen[pair[1]] = idx
            elif pair[0] in seen and pair[1] in seen:
                idx0 = seen[pair[0]]
                idx1 = seen[pair[1]]
                if idx0 != idx1:
                    # print(pair, seen, swaplists, idx0, idx1)
                    if len(swaplists[idx0]) < len(swaplists[idx1]):
                        temp = idx0
                        idx0 = idx1
                        idx1 = temp
                    swaplists[idx0] = swaplists[idx0].union(swaplists[idx1])
                    # print(len(swaplists[idx1]), swaplists[idx1])
                    for i in swaplists[idx1]:
                        seen[i] = idx0
                    swaplists[idx1] = set()


        swaplists = list(filter(lambda e: len(e), swaplists))
        # print(swaplists)

        
        # sorted_swaplists = list(map(lambda swaplist: sorted(list(swaplist)), swaplists))
        s = list(s)
        for swaplist in swaplists:
            sorted_swaplist = list(sorted(swaplist))
            letters = list(sorted(map(lambda i: s[i], sorted_swaplist)))
            # print(swaplist, letters)
            for i in range(len(sorted_swaplist)):
                s[sorted_swaplist[i]] = letters[i]
        
        return ''.join(s)

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