Find Center of Star Graph

There is an undirected star graph consisting of n nodes labeled from 1 to n. A star graph is a graph where there is one center node and exactly n - 1 edges that connect the center node with every other node.

You are given a 2D integer array edges where each edges[i] = [ui, vi] indicates that there is an edge between the nodes ui and vi. Return the center of the given star graph.

Example 1:

Input: edges = [[1,2],[2,3],[4,2]]
Output: 2

Example 2:

Input: edges = [[1,2],[5,1],[1,3],[1,4]]
Output: 1

Approach

C++

#include <bits/stdc++.h>
using namespace std;

int findCenter(vector<vector<int>> &edges)
{
    set<int> st;
    int res;
    for (int i = 0; i < edges.size(); i++)
    {

        if (st.find(edges[i][0]) != st.end())
        {
            res = edges[i][0];
            break;
        }
        else if (st.find(edges[i][0]) == st.end())
            st.insert(edges[i][0]);
        if (st.find(edges[i][1]) != st.end())
        {
            res = edges[i][1];
            break;
        }
        else
            st.insert(edges[i][1]);
    }
    return res;
}

int main()
{
    vector<vector<int>> edges = {{1, 2}, {2, 3}, {4, 2}};

    cout << findCenter(edges) << "\n";

    return 0;
}