fork(2) download 
  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 
Standard input is empty
stdout 
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:
9 years ago
visibility:
public

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