数据结构中的后序树遍历
在本章节中,我们将了解用于二叉搜索树的后序遍历技术(递归)。
假设我们有一棵这样的树 −
遍历序列为:8、5、15、23、20、16、10
算法
postorderTraverse(root): Begin if root is not empty, then postorderTraversal(left of root) postorderTraversal(right of root) print the value of root end if End
示例
#include<iostream> using namespace std; class node{ public: int h_left, h_right, bf, value; node *left, *right; }; class tree{ private: node *get_node(int key); public: node *root; tree(){ root = NULL; //set root as NULL at the beginning } void postorder_traversal(node *r); node *insert_node(node *root, int key); }; node *tree::get_node(int key){ node *new_node; new_node = new node; //create a new node dynamically new_node->h_left = 0; new_node->h_right = 0; new_node->bf = 0; new_node->value = key; //store the value from given key new_node->left = NULL; new_node->right = NULL; return new_node; } void tree::postorder_traversal(node *r){ if(r != NULL){ //When root is present, visit left - root - right postorder_traversal(r->left); postorder_traversal(r->right); cout << r->value << " "; } } node *tree::insert_node(node *root, int key){ if(root == NULL){ return (get_node(key)); //when tree is empty, create a node as root } if(key < root->value){ //when key is smaller than root value, go to the left root->left = insert_node(root->left, key); }else if(key > root->value){ //when key is greater than root value, go to the right root->right = insert_node(root->right, key); } return root; //when key is already present, do not insert it again } main(){ node *root; tree my_tree; //Insert some keys into the tree. my_tree.root = my_tree.insert_node(my_tree.root, 10); my_tree.root = my_tree.insert_node(my_tree.root, 5); my_tree.root = my_tree.insert_node(my_tree.root, 16); my_tree.root = my_tree.insert_node(my_tree.root, 20); my_tree.root = my_tree.insert_node(my_tree.root, 15); my_tree.root = my_tree.insert_node(my_tree.root, 8); my_tree.root = my_tree.insert_node(my_tree.root, 23); cout << "Post-Order Traversal: "; my_tree.postorder_traversal(my_tree.root); }
输出
Post-Order Traversal: 8 5 15 23 20 16 10
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