diff --git a/random.cpp b/random.cpp
new file mode 100644
index 0000000..482c406
--- /dev/null
+++ b/random.cpp
@@ -0,0 +1,4 @@
+#include "random.hpp"
+
+std::random_device rdevice;
+std::mt19937_64 rng::rng(rdevice());
diff --git a/random.hpp b/random.hpp
new file mode 100644
index 0000000..03fe810
--- /dev/null
+++ b/random.hpp
@@ -0,0 +1,24 @@
+#ifndef RANDOM_HPP_RANDOMNESS_WHATEVER_HEADER_238947837827_H
+#define RANDOM_HPP_RANDOMNESS_WHATEVER_HEADER_238947837827_H
+
+#include <random>
+
+namespace rng {
+	extern std::mt19937_64 rng;
+
+	template<long long start, long long end>
+	auto random_int() -> int
+	{
+		static std::uniform_int_distribution<> rint(start, end);
+		return rint(rng);
+	}
+
+	template<int start, int end>
+	auto random_double() -> double
+	{
+		static std::uniform_real_distribution<> rdouble(start, end);
+		return rdouble(rng);
+	}
+} // namespace rng
+
+#endif
diff --git a/sa.cpp b/sa.cpp
index 371ae41..203b515 100644
--- a/sa.cpp
+++ b/sa.cpp
@@ -6,11 +6,7 @@ auto sa::solution::simulated_annealing(int capacity, const std::vector<long long
                                        const double temp_min)->sa::solution
 {
 	sa::solution best(items, capacity);
-
 	sa::solution prev = best;
-	std::random_device rdevice;
-	std::default_random_engine eng(rdevice());
-	std::uniform_real_distribution<> rand(0, 1);
 
 	int iteration = 0;
 
@@ -20,7 +16,7 @@ auto sa::solution::simulated_annealing(int capacity, const std::vector<long long
 		neighbor.setneighbor();
 
 		long long diff = neighbor.fitness - prev.fitness;
-		if (diff < 0 || rand(eng) / temp < 0.8) {
+		if (diff < 0 || rng::random_double<0, 1>() / temp < 0.8) {
 			swap(prev, neighbor);
 		}
 
diff --git a/sa.hpp b/sa.hpp
index 4e7c45f..62ccf7e 100644
--- a/sa.hpp
+++ b/sa.hpp
@@ -6,11 +6,13 @@
 
 #include <algorithm>
 #include <iostream>
+#include <queue>
 #include <random>
 #include <set>
 #include <utility>
 #include <vector>
-#include <queue>
+
+#include "random.hpp"
 
 namespace sa {
 
@@ -94,7 +96,6 @@ class box {
 
 class solution {
 	std::vector<box> boxes;
-	std::mt19937_64 gen;
 	long long fitness;
 	int capacity;
 	int iterations;
@@ -104,7 +105,6 @@ class solution {
 		using std::swap;
 
 		swap(one.boxes, two.boxes);
-		swap(one.gen, two.gen);
 		swap(one.capacity, two.capacity);
 		swap(one.fitness, two.fitness);
 		swap(one.iterations, two.iterations);
@@ -122,8 +122,7 @@ class solution {
 			&sequence11
 		};
 
-		std::uniform_real_distribution<> rand(0, 1);
-		int now = rand(gen) > 0.3 ? 0 : 1;
+		int now = rng::random_double<0, 1>() > 0.3 ? 0 : 1;
 
 		if (sequences[now]->empty()) {
 			now ^= 1;
@@ -133,19 +132,17 @@ class solution {
 		}
 
 		std::uniform_int_distribution<> dist(0, (int)sequences[now]->size() - 1);
-		(boxes[choice].*swaps[now])(boxes[(*sequences[now])[dist(gen)]]);
+		(boxes[choice].*swaps[now])(boxes[(*sequences[now])[dist(rng::rng)]]);
 	}
 
 	public:
 	solution() = default;
 
-	solution(const solution &other, int itr): boxes(other.boxes), gen(other.gen),
-	                                          fitness(other.fitness), capacity(other.capacity),
-	                                          iteration(itr) {}
+	solution(const solution &other, int itr): boxes(other.boxes), fitness(other.fitness), 
+	                                          capacity(other.capacity), iteration(itr) {}
 
 	solution(const std::vector<long long> &items, int capacity):  // Gera a solução inicial
-	         gen(std::random_device()()), capacity(capacity),
-	         iteration(0) {
+	         capacity(capacity), iteration(0) {
 		std::multiset<long long> its;
 		for (auto i : items) {
 			its.insert(i);
@@ -177,7 +174,7 @@ class solution {
 	}
 
 	void setneighbor() { // Gera um vizinho da solução
-		int choice = std::uniform_int_distribution<>(0, (int)boxes.size() - 1)(gen);
+		int choice = std::uniform_int_distribution<>(0, (int)boxes.size() - 1)(rng::rng);
 		std::vector<int> sequence10;
 		std::vector<int> sequence11;
 
@@ -209,10 +206,6 @@ class solution {
 		}
 	}
 
-	void randomize() {
-		std::shuffle(boxes.begin(), boxes.end(), gen);
-	}
-
 	void print_sol(char flags = 0) {
 		if(!(flags & SIMULATED_ANNEALING_DISABLE_SHOWITRNUM)){
 			std::cout << "Iteração da solução: " << iteration << '\n';