<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 {
public:
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        vector<vector<int>> components;
        unordered_map<int, int> componentMap;
        for (auto pair: pairs) {
            if (pair[0] == pair[1]) {
                continue;
            }
            if (componentMap.find(pair[0]) == componentMap.end()) {
                if (componentMap.find(pair[1]) == componentMap.end()) {
                    components.push_back({pair[0], pair[1]});
                    componentMap[pair[0]] = components.size() - 1;
                    componentMap[pair[1]] = components.size() - 1;
                } else {
                    componentMap[pair[0]] = componentMap[pair[1]];
                    components[componentMap[pair[1]]].push_back(pair[0]);
                }
            } else {
                if (componentMap.find(pair[1]) == componentMap.end()) {
                    componentMap[pair[1]] = componentMap[pair[0]];
                    components[componentMap[pair[0]]].push_back(pair[1]);
                } else {
                    int comp0 = componentMap[pair[0]],
                        comp1 = componentMap[pair[1]];
                    vector<int> &component1 = components[comp1],
                        &component0 = components[comp0];
                    if (comp0 != comp1) {
                        if (component1.size() > component0.size()) {
                            component1.insert( component1.end(), component0.begin(), component0.end() );
                            for (int pos: component0) {
                                componentMap[pos] = comp1;
                            }
                            component0.clear();
                        } else {
                            component0.insert( component0.end(), component1.begin(), component1.end() );
                            for (int pos: component1) {
                                componentMap[pos] = comp0;
                            }
                            component1.clear();
                        }
                    }
                }
            }
        }

        for (auto component: components) {
            vector<char> letters(component.size());
            for (int i = 0; i < component.size(); i++) {
                letters[i] = s[component[i]];
            }
            sort(letters.begin(), letters.end());
            sort(component.begin(), component.end());
            for (int i = 0; i < component.size(); i++) {
                s[component[i]] = letters[i];
            }
        }
        return s;
    }
};
66312