fork(2) download
copy 
  1. #include <iostream>
  2. #include <stack>
  3.  
  4. struct leaf {
  5.     public:
  6.         int value;
  7.         leaf* right;
  8.         leaf* left;
  9.         leaf* neighbor;
  10.  
  11.         leaf(int v, leaf* r, leaf* l) :
  12.             value(v), right(r), left(l), neighbor(nullptr) {};
  13. };
  14.  
  15. void find_neighbors(leaf* node, std::stack<leaf*> & stack)
  16. {
  17.     if (node == nullptr) {
  18.         return;
  19.     };
  20.  
  21.     if (!stack.empty()) {
  22.         node->neighbor = stack.top();
  23.         stack.pop();
  24.     };
  25.  
  26.     find_neighbors(node->right, stack);
  27.     find_neighbors(node->left, stack);
  28.     stack.push(node);
  29.  
  30.     return;
  31. }
  32.  
  33. void show_leaf(leaf* node)
  34. {
  35. 	if (node == nullptr) {
  36. 		return;
  37. 	};
  38.  
  39. 	std::cout << "Node: " << node->value << " neighbor: " << (node->neighbor != nullptr ? node->neighbor->value : 0) << std::endl;
  40.  
  41. 	show_leaf(node->right);
  42. 	show_leaf(node->left);
  43.  
  44. 	return;
  45. }
  46.  
  47. int main()
  48. {
  49. 	leaf* tree0 = new leaf(1, nullptr, nullptr);
  50.  
  51. 	leaf* tree1 =
  52. 		new leaf(
  53. 			1,
  54. 			new leaf(3, nullptr, nullptr),
  55. 			new leaf(2, nullptr, nullptr)
  56. 		);
  57.  
  58. 	leaf* tree2 =
  59. 		new leaf(
  60. 			1,
  61. 			new leaf(
  62. 				3,
  63. 				new leaf(7, nullptr, nullptr),
  64. 				new leaf(6, nullptr, nullptr)
  65. 			),
  66. 			new leaf(
  67. 				2,
  68. 				nullptr,
  69. 				new leaf(4, nullptr, nullptr)
  70. 			)
  71. 		);
  72.  
  73. 	std::stack<leaf*> stack0;
  74. 	find_neighbors(tree0, stack0);
  75. 	std::cout << "Tree #0" << std::endl;
  76. 	std::cout << "(1)" << std::endl;
  77. 	show_leaf(tree0);
  78. 	std::cout << std::endl;
  79.  
  80. 	std::stack<leaf*> stack1;
  81. 	find_neighbors(tree1, stack1);
  82. 	std::cout << "Tree #1" << std::endl;
  83. 	std::cout << "   (1)" << std::endl;
  84. 	std::cout << "  /   \\" << std::endl;
  85. 	std::cout << "(2)   (3)" << std::endl;
  86. 	show_leaf(tree1);
  87. 	std::cout << std::endl;
  88.  
  89. 	std::stack<leaf*> stack2;
  90. 	find_neighbors(tree2, stack2);
  91. 	std::cout << "Tree #2" << std::endl;
  92. 	std::cout << "    (1)" << std::endl;
  93. 	std::cout << "    / \\" << std::endl;
  94. 	std::cout << "  (2)  (3)" << std::endl;
  95. 	std::cout << "  /    / \\" << std::endl;
  96. 	std::cout << "(4)  (6)  (7)" << std::endl;
  97. 	show_leaf(tree2);
  98. 	std::cout << std::endl;
  99.  
  100. 	return 0;
  101. }
Success #stdin #stdout 0s 3464KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Tree #0
(1)
Node: 1 neighbor: 0

Tree #1
   (1)
  /   \
(2)   (3)
Node: 1 neighbor: 0
Node: 3 neighbor: 0
Node: 2 neighbor: 3

Tree #2
    (1)
    / \
  (2)  (3)
  /    / \
(4)  (6)  (7)
Node: 1 neighbor: 0
Node: 3 neighbor: 0
Node: 7 neighbor: 0
Node: 6 neighbor: 7
Node: 2 neighbor: 3
Node: 4 neighbor: 6
https://ideone.com/OjNWMU
language:
C++14 (gcc 8.3)
created:
8 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!