<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:
    int n;
    vector<int> G[100005];
    string str;
    vector<int> chars;
    set<int> indices;
    void dfs(int node , vector<int>& vis) {
        // chars.insert(str[node]);
        chars[str[node]-'a']++;
        indices.insert(node);
        vis[node] = 1;
        // cout << node << endl;
        // int sz = G[node].size();
        // cout << node << " " << vis[node] << endl;
        for (int adj: G[node]) {
            if( !vis[adj] ) {
                dfs(adj, vis);
            }
        }
        return;
    }
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {

        n = s.size();
        str = s;
        for (auto pair : pairs) {
            G[pair[0]].push_back(pair[1]);
            G[pair[1]].push_back(pair[0]);
        }
        // for 
        vector<int> vis(n,0);
        string ans = s;
        vector<int> fre(26,0);
        chars = fre;
        
        for (int i = 0; i < n; i++) {

            if (!vis[i]) {
                // chars = 
                indices = {};
                // cout << chars.size() << endl;
                dfs(i, vis);
                // cout << chars.size() << endl;
                auto it1 = indices.begin();
                // auto it = chars.begin();
                // while (it != chars.end() && it1 != indices.end()) {
                //     int idx = *it1;
                //     char c = *it;
                //     // cout << idx << " " << c << endl;
                //     ans[idx] = c;
                //     it++;
                //     it1++;
                // }
                for (int i = 0; i < 26; i++) {
                    if (chars[i] > 0) {
                        while (chars[i] > 0) {
                            int idx = *it1;
                            char c = 'a' + i;
                            ans[idx] = c;
                            it1++;
                            chars[i]-=1;
                        }
                    }
                }
            }
        }

        return ans;
        
    }
};
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