zoukankan      html  css  js  c++  java
  • [LeetCode] 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 toNULL.

    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

     1 /**
     2  * Definition for binary tree with next pointer.
     3  * struct TreeLinkNode {
     4  *  int val;
     5  *  TreeLinkNode *left, *right, *next;
     6  *  TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
     7  * };
     8  */
     9 class Solution {
    10 public:
    11     void convert(TreeLinkNode *root)
    12     {
    13         if (root == NULL)
    14             return;
    15             
    16         TreeLinkNode *leftNode = root->left;
    17         TreeLinkNode *rightNode = root->right;
    18         
    19         if (leftNode && rightNode)
    20         {
    21             leftNode->next = rightNode;
    22             rightNode->next = NULL;
    23             TreeLinkNode *rightChild = leftNode->right;
    24             TreeLinkNode *leftChild = rightNode->left;
    25             if (leftChild && rightChild)
    26                 leftChild->next = rightChild;                
    27         }
    28         
    29         connect(leftNode);
    30         connect(rightNode);        
    31     }
    32     
    33     void fix(TreeLinkNode *leftNode, TreeLinkNode *rightNode)
    34     {
    35         if (leftNode == NULL)
    36             return;
    37             
    38         leftNode->next = rightNode;
    39         
    40         fix(leftNode->right, rightNode->left);
    41     }
    42     
    43     void connect(TreeLinkNode *root) {
    44         // Start typing your C/C++ solution below
    45         // DO NOT write int main() function
    46         if (root == NULL)
    47             return;
    48             
    49         convert(root);
    50         fix(root->left, root->right);
    51     }
    52 };
  • 相关阅读:
    模型评估方法
    欠拟合、过拟合、偏差、方差
    机器学习基本概念
    Hive 的基本概念
    Flume的Channel
    Flume的Sink
    Flume的Source
    Flume 安装和配置
    Flume的基本概念
    BIO & NIO & NIO常见框架
  • 原文地址:https://www.cnblogs.com/chkkch/p/2787533.html
Copyright © 2011-2022 走看看