c++14 下隨機生成 序列 區間 樹 圖等資料

class RandomData {
private:
    static const int MAXN = 1e6 + 10;
public:
    RandomData() {
        srand((unsigned)time(0));
    }

    int random(int n) {
        return (long long)rand() * rand() % n;
    }

    int random(int l, int r) {
        return random(r - l + 1) + l;
    }

    auto random_vector(int n, int val) {
        vector<int>vec;
        for(int i = 1; i <= n; i++ ) {
            vec.push_back(random(n) + val);
        }
        return vec;
    }

    auto random_interval(int n, int l, int r) {
        vector<pair<int, int> >vec;
        for(int i = 1; i <= n; i++ ) {
            int L = random(l, r);
            int R = random(l, r);
            if(L > R) {
                swap(L, R);
            }
            vec.push_back(make_pair(L, R));
        }
        return vec;
    }

    auto random_tree(int n, int m, int l = 1, int r = 1) {
        vector<tuple<int, int, int> >vec; //id father_id value
        if(n <= 2) {
            vec.push_back(make_tuple(1, 0, 1));
            return vec;
        }
        for(int i = 2; i <= n; i++ ) {
            int fa = random(i - 1) + 1;
            int val = random(l, r);
            vec.push_back(make_tuple(i, fa, val));
        }
        return vec;
    }

    auto random_graph(int n, int m, int l = 1, int r = 1) {
        bool open = 1; // 1 is direct graph and 0 is not
        vector<tuple<int, int, int> >vec = random_tree(n, m, l, r);
        map< pair<int, int>, bool > has;
        for(unsigned i = 0; i < vec.size(); i++ ) {
            int u = get<0>(vec[i]);
            int v = get<1>(vec[i]);
            has[ make_pair(u, v) ] = true;
            if(open == 0) {
                has[ make_pair(v, u) ] = true;
            }
        }
        for(int i = n; i <= m; i++ ) {
            int x, y;
            do {
                x = random(n) + 1, y = random(y) + 1;
            } while(x == y || has[ make_pair(x, y) ]);
            int val = random(l, r);
            vec.push_back(make_tuple(x, y, val));
            has[ make_pair(x, y) ] = true;
            if(open) {
                has[ make_pair(y, x) ] = true;
            }
        }
        random_shuffle(vec.begin(), vec.end());
        return vec;
    }
} random_data;