+int StdRandom::uniform_int(int min, int max)
+{
+ std::uniform_int_distribution<> dist(min, max);
+ return dist(mt19937_gen);
+}
+
+double StdRandom::uniform_real(double min, double max)
+{
+ std::uniform_real_distribution<> dist(min, max);
+ return dist(mt19937_gen);
+}
+
+double StdRandom::exponential(double lambda)
+{
+ std::exponential_distribution<> dist(lambda);
+ return dist(mt19937_gen);
+}
+
+double StdRandom::normal(double mean, double sd)
+{
+ std::normal_distribution<> dist(mean, sd);
+ return dist(mt19937_gen);
+}
+
+int XbtRandom::uniform_int(int min, int max)