將二叉樹轉換為穿針二叉樹 | 在 C++ 中使用佇列的集合 1


在本教程中,我們將討論一個使用佇列資料結構將二叉樹轉換為穿針二叉樹的程式。

為此,我們將提供一棵二叉樹。我們的任務是透過在佇列資料結構的幫助下新增額外的路由來將這棵特定的二叉樹轉換為穿針二叉樹,以實現更快速的順序遍歷。

示例

 執行演示

#include <iostream>
#include <queue>
using namespace std;
//node structure for threaded tree
struct Node {
   int key;
   Node *left, *right;
   bool isThreaded;
};
//putting the inorder pattern into a queue
void convert_queue(Node* root, std::queue<Node*>* q){
   if (root == NULL)
      return;
   if (root->left)
      convert_queue(root->left, q);
   q->push(root);
   if (root->right)
      convert_queue(root->right, q);
}
//traversing the queue and making threaded tree
void create_threadedtree(Node* root, std::queue<Node*>* q){
   if (root == NULL)
      return;
   if (root->left)
      create_threadedtree(root->left, q);
   q->pop();
   if (root->right)
      create_threadedtree(root->right, q);
   //if right pointer in NUll, point it to
   //inorder successor
   else {
      root->right = q->front();
      root->isThreaded = true;
   }
}
//finally taking the tree and converting it into threaded
void createThreaded(Node* root){
   std::queue<Node*> q;
   convert_queue(root, &q);
   create_threadedtree(root, &q);
}
Node* leftMost(Node* root){
   while (root != NULL && root->left != NULL)
      root = root->left;
      return root;
   }
   //performing inorder traversal of threaded tree
   void inOrder(Node* root){
      if (root == NULL)
         return;
      Node* cur = leftMost(root);
      while (cur != NULL) {
         cout << cur->key << " ";
         //if threaded node, move to inorder successor
         if (cur->isThreaded)
            cur = cur->right;
         else
            cur = leftMost(cur->right);
      }
   }
   Node* newNode(int key){
      Node* temp = new Node;
      temp->left = temp->right = NULL;
      temp->key = key;
      return temp;
}
int main(){
   Node* root = newNode(1);
   root->left = newNode(2);
   root->right = newNode(3);
   root->left->left = newNode(4);
   root->left->right = newNode(5);
   root->right->left = newNode(6);
   root->right->right = newNode(7);
   createThreaded(root);
   cout << "Traversing threaded tree :\n";
   inOrder(root);
   return 0;
}

輸出

Traversing threaded tree :
4 2 5 1 6 3 7

更新日期: 2020 年 1 月 2 日

330 次瀏覽

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