randomized_mvc.cpp

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <cstdlib>
#include <ctime>

using namespace std;

void remove_edges(vector<vector<int>> &graph, int n)
{
    auto it = graph.begin();
    while (it != graph.end())
    {
        if ((*it)[0] == n || (*it)[1] == n)
        {
            it = graph.erase(it);
        }
        else
        {
            it++;
        }
    }
}

vector<int> mvc(vector<vector<int>> &graph)
{
    vector<int> ans;
    srand(time(0));
    while (!graph.empty())
    {
        int i = rand() % 5;
        int u = graph[i][0];
        int v = graph[i][1];
        ans.push_back(u);
        ans.push_back(v);
        remove_edges(graph, u);
        remove_edges(graph, v);
    }
    return ans;
}

int main()
{
    set<int> ans;
    vector<vector<int>> graph{
        {0, 1},
        {0, 2},
        {1, 3},
        {3, 4},
    };
    int n = graph.size();
    vector<int> s = mvc(graph);
    for (auto x : s)
    {
        cout << x << " ";
    }

    return 0;
}

// output
// 0 1 3 4