Change the algorithm for the neighbor set

sa.cpp

@@ -21,7 +21,7 @@ auto sa::solution::simulated_annealing(int capacity, const std::vector<long long
 
 		int diff = neighbor.fitness - prev.fitness;
 		if (diff <= 0 || std::exp(-diff / temp) > rand(eng)) {
-			prev.swap(neighbor);
+			swap(prev, neighbor);
 		}
 
 		temp *= alpha;

sa.hpp

@@ -1,54 +1,110 @@
 #ifndef SIMULATED_ANNEALING_HEADER_12647_H
 #define SIMULATED_ANNEALING_HEADER_12647_H
+
 #define SIMULATED_ANNEALING_DISABLE_SHOWCRATES 1
 #define SIMULATED_ANNEALING_DISABLE_SHOWITRNUM 2
 
 #include <algorithm>
 #include <iostream>
-#include <queue>
 #include <random>
-#include <vector>
 #include <set>
+#include <vector>
 
 namespace sa {
 
+class box {
+	std::multiset<long long> items;
+	long long fullness{};
+
+	friend void swap(box &one, box &two) {
+		using std::swap;
+
+		swap(one.items, two.items);
+		swap(one.fullness, two.fullness);
+	}
+
+	public:
+
+	box() = default;
+
+	box(const std::multiset<long long> &multiset, long long fullness):
+	    items(multiset), fullness(fullness) {}
+
+	void add_item(long long item) {
+		fullness += item;
+		items.insert(item);
+	}
+
+	void clear() {
+		items.clear();
+		fullness = 0;
+	}
+
+	void pop() {
+		fullness -= *items.begin();
+		items.erase(items.begin());
+	}
+
+	auto swap10(box &other, int capacity) -> bool {
+		if (*items.begin() + other.fullness > capacity) {
+			return false;
+		}
+		other.add_item(*items.begin());
+		pop(); return true; }
+
+	auto swap11(box &other, int capacity) -> bool {
+		long long choice1 = *items.begin();
+		long long choice2 = *other.items.begin();
+
+		if (choice1 + other.fullness - choice2 > capacity ||
+		    choice2 + fullness - choice1 > capacity) {
+		    	return false;
+		}
+
+		pop();
+		other.pop();
+		add_item(choice2);
+		other.add_item(choice1);
+
+		return true;
+	}
+
+	void print(int ind) const {
+		std::cout << "Caixa " << ind << ":";
+		for (auto item : items) {
+			std::cout << ' ' << item;
+		}
+		std::cout << '\n';
+	}
+
+	[[nodiscard]] auto empty() const -> bool {
+		return fullness == 0;
+	}
+};
+
 class solution {
-	std::vector<long long> items;
+	std::vector<box> boxes;
 	std::default_random_engine gen;
 	int capacity;
 	int fitness;
 	int iterations;
 	int iteration;
 
-	auto calculate_boxes()->int {
-		int count = 1;
-		long long now = 0;
+	friend void swap(solution &one, solution &two) {
+		using std::swap;
 
-		for (auto i : items) {
-			if (now + i > capacity) {
-				count++;
-				now = i;
-				continue;
-			}
-			now += i;
-		}
-
-		return count;
-	}
-
-	static void print_box(int box, std::queue<long long> &stored) {
-		std::cout << "Caixa " << box << ":";
-		while (!stored.empty()) {
-			std::cout << ' ' << stored.front();
-			stored.pop();
-		}
-		std::cout << '\n';
+		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);
+		swap(one.iteration, two.iteration);
 	}
 
 	public:
 	solution() = default;
 
-	solution(const solution &other, int itr): items(other.items), gen(other.gen),
+	solution(const solution &other, int itr): boxes(other.boxes), gen(other.gen),
 	                                          capacity(other.capacity), fitness(other.fitness),
 	                                          iteration(itr) {}
 
@@ -60,10 +116,8 @@ class solution {
 			its.insert(i);
 		}
 
-			 this->items.resize(items.size());
-			 size_t i = 0;
-
 		long long cap = capacity;
+		box tmp;
 
 		while (!its.empty()) {
 			auto itr = its.upper_bound(cap);
@@ -71,40 +125,55 @@ class solution {
 	        		cap = capacity;
 	        		cap -= *its.begin();
 	        		itr = its.begin();
+	        		this->boxes.emplace_back(tmp);
+	        		tmp.clear();
 			} else {
 				itr--;
 				cap -= *itr;
 			}
-				this->items[i] = *itr;
+			tmp.add_item(*itr);
 			its.erase(itr);
-				i++;
 		}
 
-			fitness = calculate_boxes();
+		if (!tmp.empty()) {
+			this->boxes.emplace_back(tmp);
+		}
+		fitness = (int)this->boxes.size();
 	}
 
 	void setneighbor() { // Gera um vizinho da solução
-		std::uniform_int_distribution<> dist(0, items.size() - 1);
-		int first = dist(gen);
-		int second = 0;
-		while ((second = dist(gen)) == first) {}
+		std::uniform_int_distribution<> dist(0, (int)boxes.size() - 1);
 
-		std::swap(items[first], items[second]);
-		fitness = calculate_boxes();
+		int choice = dist(gen);
+		std::vector<int> sequence(boxes.size() - 1);
+		for (size_t i = 0; i < choice; i++) {
+			sequence[i] = i;
+		}
+		for (size_t i = choice + 1; i < boxes.size(); i++) {
+			sequence[i - 1] = i;
+		}
+
+		shuffle(sequence.begin(), sequence.end(), gen);
+
+		for (auto ind : sequence) {
+			if (boxes[choice].swap10(boxes[ind], capacity)) {
+				if (boxes[choice].empty()) {
+					boxes.erase(boxes.begin() + choice);
+				}
+				fitness = (int)boxes.size();
+				return;
+			}
+		}
+
+		for (auto ind : sequence) {
+			if (boxes[choice].swap11(boxes[ind], capacity)) {
+				return;
+			}
+		}
 	}
 
 	void randomize() {
-		std::shuffle(items.begin(), items.end(), gen);
-
-		fitness = calculate_boxes();
-	}
-
-	void swap(solution &other) {
-		std::swap(fitness, other.fitness);
-		std::swap(items, other.items);
-		std::swap(capacity, other.capacity);
-		std::swap(gen, other.gen);
-		std::swap(iteration, other.iteration);
+		std::shuffle(boxes.begin(), boxes.end(), gen);
 	}
 
 	void print_sol(char flags = 0) const {
@@ -115,23 +184,9 @@ class solution {
 		std::cout << "Número de caixas: " << fitness << '\n';
 
 		if(!(flags & SIMULATED_ANNEALING_DISABLE_SHOWCRATES)){
-			int box_now = 1;
-			long long now = 0;
-			std::queue<long long> items_stored;
-
-			for (auto i : items) {
-				if (now + i > capacity) {
-					print_box(box_now, items_stored);
-					box_now++;
-					now = i;
-				} else {
-					now += i;
+			for (size_t i = 0; i < boxes.size(); i++) {
+				boxes[i].print((int)i + 1);
 			}
-				items_stored.push(i);
-			}
-
-			print_box(box_now, items_stored);
-			std::cout << '\n';
 		}
 	}
 
@@ -141,7 +196,7 @@ class solution {
 
 	static auto simulated_annealing(int capacity, const std::vector<long long> &items,
 	                                double alpha, double temp,
-	                                double temp_min)->solution;
+	                                double temp_min) -> solution;
 };
 
 } // namespace sa