C/C++程序基础 （八）数据结构

1. 非递归先序遍历
   • 　　

     // 输出， 遍历左子树，遍历右子树
     void firstOrder(Node* root)
     {
        stack<Node*> leftNodes;
        Node* curr = root;
     
       // deal each node
        while(curr != NULL && !leftNodes.empty())
        {
           // deal with left subtree
           while(curr != NULL)
           {
              cout << curr -> data << " ";
              // store curr node for reading right subtree
              leftNodes.push(curr);
              curr = curr -> left;
           }
     
           // deal with right subtree
          if(!leftNodes.empty())
          {
              curr = leftNodes.top();
              leftNodes.pop();
     
              curr = curr -> right;
           }
        }
     }

2. 非递归中序遍历

   • // 输出， 遍历左子树，遍历右子树
     void middleOrder(Node* root)
     {
        stack<Node*> leftNodes;
        Node* curr = root;
     
       // deal each node
        while(curr != NULL && !leftNodes.empty())
        {
           // deal with left subtree
           while(curr != NULL)
           {
              // store curr node for reading right subtree
              leftNodes.push(curr);
              curr = curr -> left;
           }
     
           // deal with right subtree
          if(!leftNodes.empty())
          {
              curr = leftNodes.top();
              leftNodes.pop();
              // cout curr node
              cout << curr -> data << " ";
     
              curr = curr -> right;
           }
        }
     }

     　　

3. 非递归后序遍历

   • // 输出， 遍历左子树，遍历右子树
     void lastOrder(Node* root)
     {
        stack<Node*> leftNodes;
        stack<bool> tags;
        bool curr_tag = true;
        Node* curr = root;
     
       // deal each node
        while(curr != NULL && !leftNodes.empty())
        {
           // deal with left subtree
           while(curr != NULL)
           {
              // store curr node for reading right subtree
              leftNodes.push(curr);
     
              // mark have not seen right nodes
              tags.push(false);
              curr = curr -> left;
           }
     
           // deal with right subtree
          if(!leftNodes.empty())
          {
              curr = leftNodes.top();
              curr_tag = tags.top();
              tags.pop();
     
              if(curr_tag)
              {
                  cout << curr -> data << " ";
                  leftNodes.pop();
                  // have already dealt right subtree
                  p = NULL;
              }
              else
              {
                  curr = curr -> right;
                  // mark has dealt with rightsubtree
                  tags.push(true);
              }
           }
        }
     }

4. 二叉排序树：左<父<右
5. 哈弗曼树
   • 哈夫曼编码：带权路径最短
   • 构建方法：从最远端构建
6. 平衡二叉（搜索）树：每个节点的左右子树深度差的绝对值小于等于1。
   • 一种实现：红黑树
   • 基本失衡情况：左左（右旋），右右（左旋），左右，右左。
7. 红黑树
   • 节点：红色或黑色。根节点：黑色。叶节点：黑色。红色节点的孩子为黑色。根节点到其每个叶子节点的所有路径包含相同数目的黑色节点。
   • 等待补充
8. 完全二叉树和满二叉树
   • 完全二叉树，集中在左边
   • 满二叉树，没有叶子节点