treegen.cpp

#include <algorithm>
#include <utility>
#include <functional>
#include <vector>
#include <utility>
#include <random>
#include <iostream>

using namespace std;

//-----Tooster-----

int n, maxChildCount, firstVertex;
int main(int argc, char *argv[]) {
    ios_base::sync_with_stdio(false);
    if (argc == 1) {
        int a;
        cin >> a >> n >> maxChildCount >> firstVertex;
        srand(atoi("treegen") + a);
    }
    else if (argc == 5) {
        srand(atoi(argv[0]) + atoi(argv[1]));
        n = atoi(argv[2]);
        maxChildCount = atoi(argv[3]);
        firstVertex = atoi(argv[4]);
    }
    else {
        cerr << "Usage: <randomSeed> <vertices> <maxChildCount> <firstVertex>" << endl;
        cerr << "   randomSeed     - seed for random number generator, e.g. test number" << endl;
        cerr << "   vertices       - number of vertices" << endl;
        cerr << "   maxChildCount  - maximum number of edges connected to one vertex" << endl;
        cerr << "   firstVertex    - vertices enumeration start" << endl;
        cerr << endl;
        cerr << " output format: N pairs {A, B} : A is connected with bidirectional edge with B" << endl;
        return 1;
    }

    vector<vector <int> > V(n);
    vector<int> hashTable(n);
    for (int i = 0; i < n; i++) hashTable[i] = i;
    random_shuffle(hashTable.begin(), hashTable.end());

    int v = 1;
    while (v < n) {
        int u = rand() % v;
        int children = rand() % maxChildCount + 1;
        while (v < n && children > 0 && V[u].size() < maxChildCount - 1) {
            V[u].push_back(v++);
            children--;
        }
    }

    for (int i = 0; i < V.size(); i++)
        for (int j = 0; j < V[i].size(); j++)
            cout << hashTable[i] + firstVertex << " " << hashTable[V[i][j]] + firstVertex << endl;

    return 0;
}