<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) {
        unordered_map<int, vector<int>> adj_list;

        for(auto& edge : pairs)
        {
            adj_list[edge[0]].emplace_back(edge[1]);
            adj_list[edge[1]].emplace_back(edge[0]);
        }

        string result(s.size(), ' ');

        unordered_set<int> visit;
        

        for(int idx = 0; idx < s.size(); idx++)
        {
            vector<char> chars;
        vector<int> indices;
            if(DFS(idx, s, adj_list, visit, chars, indices))
            {
                sort(chars.begin(), chars.end());
                sort(indices.begin(), indices.end());
                for(int i = 0; i < indices.size(); i++)
                {
                    result[indices[i]] = chars[i];
                }
            }
        }

        return result;
        // for(auto& edge : adj_list)
        // {
        //     stack<int> s{edge.first};
        //     vector<char> chars;
        //     vector<int> indices;
        //     while(!s.empty())
        //     {
        //         int cur = s.top();
        //         s.pop();
        //         if(visit.count(cur))
        //         {
        //             continue;
        //         }

        //     }
        // }
    

        //s.push(adj_list.front());
    }

    bool DFS(int cur, string& input,  unordered_map<int, vector<int>>& adj_list, unordered_set<int>& visit, vector<char>& chars, vector<int>& indices)
    {
        if(visit.count(cur))
        {
            return false;
        }

        visit.insert(cur);
        chars.push_back(input[cur]);
        indices.push_back(cur);


        for(auto& edge : adj_list[cur])
        {
            DFS(edge, input, adj_list, visit, chars, indices);
        }

        return true;
    }
};
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