zoukankan      html  css  js  c++  java
  • [leetcode] Populating Next Right Pointers in Each Node

    Populating Next Right Pointers in Each Node

    Given a binary tree

        struct TreeLinkNode {
          TreeLinkNode *left;
          TreeLinkNode *right;
          TreeLinkNode *next;
        }
    

    Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL.

    Initially, all next pointers are set to NULL.

    Note:

    • You may only use constant extra space.
    • You may assume that it is a perfect binary tree (ie, all leaves are at the same level, and every parent has two children).

    For example,
    Given the following perfect binary tree,

             1
           /  
          2    3
         /   / 
        4  5  6  7
    

    After calling your function, the tree should look like:

             1 -> NULL
           /  
          2 -> 3 -> NULL
         /   / 
        4->5->6->7 -> NULL
    
    思路:树的层次遍历,每层的最后一个节点next值为NULL。
    
    /**
     * Definition for binary tree with next pointer.
     * struct TreeLinkNode {
     *  int val;
     *  TreeLinkNode *left, *right, *next;
     *  TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
     * };
     */
    class Solution
    {
    public:
      void connect(TreeLinkNode *root)
      {
        queue<TreeLinkNode *> myque;
        if(NULL == root) return;
    
        myque.push(root);
        int size = 0;
        while(!myque.empty())
        {
          size = myque.size();
          for(int i=0; i<size; i++)
          {
            TreeLinkNode *cur = myque.front();
            myque.pop();
    
            if(i<size-1)
              cur->next = myque.front();
    
            if(cur->left) myque.push(cur->left);
            if(cur->right) myque.push(cur->right);
          }
        }
      }
    };

  • 相关阅读:
    数据结构与算法分析-二叉堆
    数据结构与算法分析-AVL树
    数据结构与算法分析-二叉查找树
    优秀程序员应具备的15个特性
    2016年1月22日 收盘后美加的走势
    2016年1月8日 12月非农数据
    Replace into 与Insert into on duplicate key update的区别
    MYSQL视图的学习笔记
    postgresql创建用户
    连接postgresql数据库
  • 原文地址:https://www.cnblogs.com/lxd2502/p/4484605.html
Copyright © 2011-2022 走看看