<p>In this problem, a tree is an <strong>undirected graph</strong> that is connected and has no cycles.</p>

<p>You are given a graph that started as a tree with <code>n</code> nodes labeled from <code>1</code> to <code>n</code>, with one additional edge added. The added edge has two <strong>different</strong> vertices chosen from <code>1</code> to <code>n</code>, and was not an edge that already existed. The graph is represented as an array <code>edges</code> of length <code>n</code> where <code>edges[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> indicates that there is an edge between nodes <code>a<sub>i</sub></code> and <code>b<sub>i</sub></code> in the graph.</p>

<p>Return <em>an edge that can be removed so that the resulting graph is a tree of </em><code>n</code><em> nodes</em>. If there are multiple answers, return the answer that occurs last in the input.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/05/02/reduntant1-1-graph.jpg" style="width: 222px; height: 222px;" />
<pre>
<strong>Input:</strong> edges = [[1,2],[1,3],[2,3]]
<strong>Output:</strong> [2,3]
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/05/02/reduntant1-2-graph.jpg" style="width: 382px; height: 222px;" />
<pre>
<strong>Input:</strong> edges = [[1,2],[2,3],[3,4],[1,4],[1,5]]
<strong>Output:</strong> [1,4]
</pre>

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

<ul>
	<li><code>n == edges.length</code></li>
	<li><code>3 &lt;= n &lt;= 1000</code></li>
	<li><code>edges[i].length == 2</code></li>
	<li><code>1 &lt;= a<sub>i</sub> &lt; b<sub>i</sub> &lt;= edges.length</code></li>
	<li><code>a<sub>i</sub> != b<sub>i</sub></code></li>
	<li>There are no repeated edges.</li>
	<li>The given graph is connected.</li>
</ul>

class Solution {
public:
    vector<int> findRedundantConnection(vector<vector<int>>& edges) {
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout.tie(NULL);

        vector<set<int>> nodes;
        int a = -1, b = -1;

        for(int i=0; i<edges.size(); i++)
        {
            a = -1, b = -1;

            for(int j=0; j<nodes.size(); j++)
            {
                if(nodes[j].find(edges[i][0])!= nodes[j].end())
                    a = j;
                if(nodes[j].find(edges[i][1])!= nodes[j].end())
                    b = j;
                if(a!=-1 && b!=-1)
                    break;
            }
            if(a==-1 && b==-1)
                nodes.push_back(set<int>(edges[i].begin(), edges[i].end()));
            else if(a==b)
                return edges[i];
            else if(a==-1)
                nodes[b].insert(edges[i][0]);
            else if(b==-1)
                nodes[a].insert(edges[i][1]);
            else
            {
                nodes[a].insert(nodes[b].begin(), nodes[b].end());
                nodes.erase(nodes.begin()+b);
            }
        }
        return {};
    }
};
15583