fork(1) download 
  1. #include <algorithm>
  2. #include <iomanip>
  3. #include <iostream>
  4. #include <memory>
  5. #include <vector>
  6. using namespace std;
  7.  
  8. class Counter {
  9. public:
  10. 	Counter()  { ++count_; }
  11. 	~Counter() { --count_; }
  12. 	static int count() { return count_; }
  13. private:
  14. 	static int count_;
  15. };
  16.  
  17. int Counter::count_ = 0;
  18.  
  19. /// Modified code starts here
  20.  
  21. class MyGraph {
  22. public:
  23. 	~MyGraph() {
  24. 		for(auto n: nodes)
  25. 			n->children.clear();
  26. 	}
  27.  
  28. 	class Node : public Counter, public enable_shared_from_this<Node> {
  29. 		vector<shared_ptr<Node>> children;
  30. 		MyGraph* owner;
  31. 		bool visited;
  32. 		friend class MyGraph;
  33.  
  34. 		void setOwner(MyGraph* graph) {
  35. 			if (owner && owner != graph)
  36. 				throw "Can't share nodes between graphs";
  37. 			if (owner)
  38. 				return;
  39.  
  40. 			owner = graph;
  41. 			graph->registerNode(shared_from_this());
  42. 		}
  43.  
  44. 	public:
  45. 		Node() : visited(false), owner(nullptr) {}
  46. 		void AddChild(const shared_ptr<Node>& node) {
  47. 			children.push_back(node);
  48. 			node->setOwner(owner);
  49. 		}
  50.  
  51.  
  52. 		void RemoveChild(const shared_ptr<Node>& node) {
  53. 			children.erase(std::remove(children.begin(), children.end(), node), children.end());
  54. 		}
  55. 	};
  56.  
  57. 	void SetRoot(const shared_ptr<Node>& node) {
  58. 		root = node;
  59. 		node->setOwner(this);
  60. 	}
  61.  
  62. 	void registerNode(const shared_ptr<Node>& node) {
  63. 		nodes.push_back(node);
  64. 	}
  65.  
  66. 	void ShrinkToFit() {
  67. 		for(auto n: nodes)
  68. 			n->visited = false;
  69.  
  70. 		visit(root);
  71. 		nodes.erase(std::remove_if(nodes.begin(), nodes.end(), [](shared_ptr<Node>& n) {
  72. 			if (n->visited)
  73. 				return false;
  74. 			n->children.clear();
  75. 			return true;
  76. 		}), nodes.end());
  77. 	}
  78.  
  79. 	void visit(const shared_ptr<Node>& n) {
  80. 		if (n->visited) 
  81. 			return;
  82.  
  83. 		n->visited = true;
  84. 		for(auto c: n->children)
  85. 			visit(c);
  86. 	}
  87.  
  88. 	static shared_ptr<MyGraph::Node> MakeNode() { 
  89. 		return make_shared<MyGraph::Node>(); 
  90. 	}
  91.  
  92. private:
  93. 	shared_ptr<Node> root;
  94. 	vector<shared_ptr<Node>> nodes;
  95. };
  96.  
  97. /// End modified code
  98. bool TestCase1() {
  99. 	MyGraph g;
  100. 	{
  101. 		auto a = MyGraph::MakeNode();
  102. 		g.SetRoot(a);
  103. 		auto b = MyGraph::MakeNode();
  104. 		a->AddChild(b);
  105. 		auto c = MyGraph::MakeNode();
  106. 		b->AddChild(c);
  107. 		a->RemoveChild(b);
  108. 	}
  109. 	g.ShrinkToFit();
  110. 	return Counter::count() == 1;
  111. }
  112.  
  113. bool TestCase2() {
  114. 	MyGraph g;
  115. 	{
  116. 		auto a = MyGraph::MakeNode();
  117. 		g.SetRoot(a);
  118. 		auto b = MyGraph::MakeNode();
  119. 		a->AddChild(b);
  120. 		auto c = MyGraph::MakeNode();
  121. 		b->AddChild(c);
  122. 		auto d = MyGraph::MakeNode();
  123. 		b->AddChild(d);
  124. 		d->AddChild(b);
  125. 		a->RemoveChild(b);
  126. 	}
  127. 	g.ShrinkToFit();
  128. 	return Counter::count() == 1;
  129. }
  130.  
  131. bool TestCase3() {
  132. 	MyGraph g;
  133. 	{
  134. 		auto a = MyGraph::MakeNode();
  135. 		g.SetRoot(a);
  136. 		auto b = MyGraph::MakeNode();
  137. 		a->AddChild(b);
  138. 		auto c = MyGraph::MakeNode();
  139. 		b->AddChild(c);
  140. 		auto d = MyGraph::MakeNode();
  141. 		b->AddChild(d);
  142. 		d->AddChild(b);
  143. 	}
  144. 	g.ShrinkToFit();
  145. 	return Counter::count() == 4;
  146. }
  147.  
  148.  
  149. bool TestCase4() { // New test case
  150. 	MyGraph g;
  151. 	{
  152. 		auto a = MyGraph::MakeNode();
  153. 		g.SetRoot(a);
  154. 		auto b = MyGraph::MakeNode();
  155. 		a->AddChild(b);
  156. 		auto c = MyGraph::MakeNode();
  157. 		b->AddChild(c);
  158. 		auto d = MyGraph::MakeNode();
  159. 		b->AddChild(d);
  160. 		d->AddChild(b);
  161. 		d->RemoveChild(b);
  162. 	}
  163. 	g.ShrinkToFit();
  164. 	return Counter::count() == 4;
  165. }
  166.  
  167. int main() {
  168. 	cout.setf(ios::boolalpha);
  169. 	bool passed1 = TestCase1();
  170. 	cout << passed1 << endl;
  171. 	bool passed2 = TestCase2();
  172. 	cout << passed2 << endl;
  173. 	bool passed3 = TestCase3();
  174. 	cout << passed3 << endl;
  175.  
  176. 	bool passed4 = TestCase4();
  177. 	cout << passed4 << endl;
  178. 	return 0;
  179. }
Success #stdin #stdout 0s 3500KB
comments (?)
stdin 
Standard input is empty
stdout 
true
true
true
true
https://ideone.com/jgXzcc
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!