zoukankan      html  css  js  c++  java
  • 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

    还是层序遍历的思想:
    /**
     * Definition for binary tree with next pointer.
     * public class TreeLinkNode {
     *     int val;
     *     TreeLinkNode left, right, next;
     *     TreeLinkNode(int x) { val = x; }
     * }
     */
    public class Solution {
        public void connect(TreeLinkNode root) {
            if(root==null) return;
            List<TreeLinkNode> level_list = new ArrayList<TreeLinkNode>();//存储当前层节点
            List<TreeLinkNode> tmp_list = new ArrayList<TreeLinkNode>();//存储下层节点
            level_list.add(root);
            int flag = 1;
            while(flag==1) {
                flag = 0;
                tmp_list.clear();
                for(int i=0;i<level_list.size();i++) {
                    if(level_list.get(i).left!=null) {
                        tmp_list.add(level_list.get(i).left);
                        flag = 1;
                    }
                    if(level_list.get(i).right!=null) {
                        tmp_list.add(level_list.get(i).right);
                        flag = 1;
                    }
                    if(i==level_list.size()-1) level_list.get(i).next = null;
                    else level_list.get(i).next = level_list.get(i+1);
                }
                level_list.clear();
                level_list.addAll(tmp_list);
            }
        }
    }
  • 相关阅读:
    触发器trigger
    VS UFT-8 保存该文件将不会保留原始内容
    SQL SERVER 单个用户模式
    vue functional函数式组件
    一维数组转树形结构
    题解 P1081 【开车旅行】
    题解 P5022 【旅行】
    题解 P2296 【寻找道路】
    题解 P2052 【[NOI2011]道路修建】
    题解 P2342 【叠积木】
  • 原文地址:https://www.cnblogs.com/mrpod2g/p/4430245.html
Copyright © 2011-2022 走看看