PerfectHashing/Graph.h at master · kislN/PerfectHashing · GitHub

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#ifndef PERFECTHASHING_GRAPH_H
#define PERFECTHASHING_GRAPH_H


UI mod(int a, int b) {
    return (a % b + b) % b;
}

struct ADJ_VERTEX {
    UI vertex;
    UI weight;
};


class Graph {
private:
    UI graph_size;
    UI edges_num;
    vector<vector<ADJ_VERTEX>> adj_list;
    vector<UI> node_marks;  /// Vector with values of the function g()
    vector<vector<UI>> connect_comp;
    vector<UI> connect_list;


public:
    Graph(size_t V, size_t E) {
        graph_size = V;
        edges_num = E;
        adj_list.resize(graph_size, vector<ADJ_VERTEX>{});
        node_marks.resize(graph_size, INF);
        connect_list.resize(graph_size);


    }

    bool generate_rand(vector<pair<UI, UI>> & nodes_pairs) {
        vector<bool> used(graph_size, false);
        UI comp_count = 1;
        for (UI i = 0; i < edges_num; ++i){
            UI node_1 = nodes_pairs[i].first;
            UI node_2 = nodes_pairs[i].second;
            if (node_1 != node_2) {
                if ((!used[node_1]) and (!used[node_2])){
                    adj_list[node_1].push_back(ADJ_VERTEX{node_2, i});
                    adj_list[node_2].push_back(ADJ_VERTEX{node_1, i});
                    connect_list[node_1] = comp_count;
                    connect_list[node_2] = comp_count;
                    comp_count++;
                    connect_comp.push_back(vector<UI>{node_1, node_2});
                    used[node_1] = true;
                    used[node_2] = true;
                    continue;
                }
                else if ((used[node_1]) and (!used[node_2])){
                    adj_list[node_1].push_back(ADJ_VERTEX{node_2, i});
                    adj_list[node_2].push_back(ADJ_VERTEX{node_1, i});
                    connect_list[node_2] = connect_list[node_1];
                    connect_comp[connect_list[node_1] - 1].push_back(node_2);
                    used[node_2] = true;
                    continue;
                }
                else if ((!used[node_1]) and (used[node_2])){
                    adj_list[node_1].push_back(ADJ_VERTEX{node_2, i});
                    adj_list[node_2].push_back(ADJ_VERTEX{node_1, i});
                    connect_list[node_1] = connect_list[node_2];
                    connect_comp[connect_list[node_2] - 1].push_back(node_1);
                    used[node_1] = true;
                    continue;
                }
                else if ((used[node_1]) and (used[node_2])){
                    if (connect_list[node_1] != connect_list[node_2]){
                        adj_list[node_1].push_back(ADJ_VERTEX{node_2, i});
                        adj_list[node_2].push_back(ADJ_VERTEX{node_1, i});

                        connect_comp[connect_list[node_1] - 1].insert(connect_comp[connect_list[node_1] - 1].end(),
                                connect_comp[connect_list[node_2] - 1].begin(),
                                connect_comp[connect_list[node_2] - 1].end());

                        UI temp_comp = connect_list[node_2] - 1;
                        for (auto x: connect_comp[connect_list[node_2] - 1]){
                            connect_list[x] = connect_list[node_1];
                        }

                        connect_comp[temp_comp].clear();
                        continue;
                    }
                    else {
                        adj_list.clear();
                        adj_list.resize(graph_size, vector<ADJ_VERTEX>{});
                        connect_comp.clear();
                        connect_list.clear();
                        connect_list.resize(graph_size);
                        return false;
                    }

                }
            }
            else {
                adj_list.clear();
                adj_list.resize(graph_size, vector<ADJ_VERTEX>{});
                connect_comp.clear();
                connect_list.clear();
                connect_list.resize(graph_size);
                return false;
            }
        }
        return true;

    }

    void update_marks() {
        vector<bool> used(graph_size, false);
        queue<UI> q;

        for (size_t i = 0; i < graph_size; i++) {

            if ((!adj_list[i].empty()) and (!used[i])) {
                node_marks[i] = 0;
                used[i] = true;
                q.push(i);
            }
            else {
                continue;
            }

            while (!q.empty()) {
                UI v1 = q.front();
                q.pop();
                for (size_t j = 0; j < adj_list[v1].size(); ++j) {
                    UI v2 = adj_list[v1][j].vertex;
                    UI weight = adj_list[v1][j].weight;
                    if (!used[v2]) {
                        node_marks[v2] = mod(int(weight - node_marks[v1]), edges_num);
                        used[v2] = true;
                        q.push(v2);
                    }
                }
            }
        }

    }

    vector<UI> & get_node_marks(){
        return node_marks;
    }

    bool is_empty() {
        for (UI i = 0; i < graph_size; ++i) {
            if (!adj_list[i].empty())
                return 0;
        }
        return 1;
    }

    void print_adj_list() {
        if (this->is_empty())
            cout << "List is empty" << endl;
        else {
            for (UI i = 0; i < graph_size; ++i) {
                cout << "vert " << i << ": ";
                for (UI j = 0; j < adj_list[i].size(); ++j) {
                    cout << adj_list[i][j].vertex << " ";
                }
                cout << endl;
            }
        }
    }

    void print_adj_with_weights() {      // Print adjacency with the weights of edges in edges_list.
        if (this->is_empty())
            cout << "List is empty" << endl;
        else {
            for (UI i = 0; i < graph_size; ++i) {
                cout << "vert " << i << ": ";
                for (UI j = 0; j < adj_list[i].size(); ++j) {
                    cout << adj_list[i][j].vertex << "(" << adj_list[i][j].weight << ") ";
                }
                cout << endl;
            }
        }
    }
};

#endif //PERFECTHASHING_GRAPH_H