LeetCode - Binary Tree Level Order Traversal
来源:互联网 发布:成都专业seo营销公司 编辑:程序博客网 时间:2024/05/23 14:56
题目描述:
Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level).
For example:
Given binary tree [3,9,20,null,null,15,7]
,
3 / \ 9 20 / \ 15 7
return its level order traversal as:
[ [3], [9,20], [15,7]]
二叉树的层序遍历,但是和往常不一样的是需要对每一层都有一个向量储存,应该要考虑到节点深度的问题,所以用pair将节点和深度组合起来,这样每次遍历都记录节点的深度,然后在最后的处理时,把节点按照深度放进各个向量中。注意层序遍历是由队列实现的,它能保证下一层的节点遍历的顺序必定在前一层节点之后,恰好满足层序遍历的要求。
class Solution {public: vector<vector<int> > levelOrder(TreeNode* root) {queue<pair<TreeNode*,int> > q; vector<pair<int,int> > v;if(root==NULL) { vector<vector<int> > result; return result;}else if(root!=NULL){pair<TreeNode*,int> p;p.first=root;p.second=0;q.push(p);while(!q.empty()){p=q.front();pair<int,int> x;x.first=p.first->val;x.second=p.second;v.push_back(x);q.pop();if(p.first->left!=NULL){pair<TreeNode*,int> l;l.first=p.first->left;l.second=p.second+1;q.push(l);}if(p.first->right!=NULL){pair<TreeNode*,int> r;r.first=p.first->right;r.second=p.second+1;q.push(r);}}}int n=v.size();int m=v[n-1].second;vector<vector<int> > result(m+1);for(int i=0;i<n;i++){result[v[i].second].push_back(v[i].first);}return result; }};
0 0
- LeetCode[Tree]: Binary Tree Level Order Traversal
- *(leetcode) Binary Tree Level Order Traversal (tree)
- [leetcode][tree] Binary Tree Level Order Traversal
- LeetCode: Binary Tree Level Order Traversal
- LeetCode: Binary Tree Zigzag Level Order Traversal
- LeetCode: Binary Tree Level Order Traversal II
- [LeetCode]Binary Tree Level Order Traversal
- [LeetCode]Binary Tree Level Order Traversal II
- [LeetCode]Binary Tree Zigzag Level Order Traversal
- LeetCode Binary Tree Level Order Traversal
- LeetCode Binary Tree Level Order Traversal II
- LeetCode Binary Tree Zigzag Level Order Traversal
- [Leetcode] Binary Tree Level Order Traversal
- [Leetcode] Binary Tree Level Order Traversal II
- [Leetcode] Binary Tree Zigzag Level Order Traversal
- Leetcode: Binary Tree Zigzag Level Order Traversal
- LeetCode Binary Tree Level Order Traversal
- LeetCode Binary Tree Level Order Traversal II
- css 初步入门
- 当想放弃的时候告诉自己!!!
- MYSQL基础语法
- 字符串与字符数组的区别
- storm集群基础+部署
- LeetCode - Binary Tree Level Order Traversal
- GoKit三种配置方式
- 微信应用号(小程序)公测后估计多久正式开放?
- MYSQL进阶
- 在HTML中引入JavaScript
- 数据库的相关函数
- 蓄水池抽样基于MapReduce的实现
- OGNL入门
- Java基础