#include "graph.hpp"
#include <algorithm>
#include <iostream>
#include <random>
#include <vector>

template <typename RNG>
bool erasedConfigurationModel(DegreeSequence &ds, Graph &g, RNG &rng) {
    // List of all half-edges
    std::vector<unsigned int> halfEdges;
    for (unsigned int i = 0; i < ds.size(); ++i)
        halfEdges.insert(halfEdges.end(), ds[i], i);

    // Clear the graph
    g.reset(ds.size());

    if (halfEdges.size() % 2 != 0)
        return false;

    std::shuffle(halfEdges.begin(), halfEdges.end(), rng);
    // pair halfEdges[2*i] with halfEdges[2*i+1]
    for (auto iter = halfEdges.begin(); iter != halfEdges.end();) {
        auto u = *iter++;
        auto v = *iter++;
        if (u != v)
            g.addEdge({u, v}); // checks for double edges
    }

    return true;
}