515. Find Largest Value in Each Tree Row（第六周）

You need to find the largest value in each row of a binary tree.

Example:

Input: 1 / \ 3 2 / \ \ 5 3 9 Output: [1, 3, 9]

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解题思路：

遍历还是通过dfs遍历，只是增加一个tag来判断该数是不是处于同一层次的（同一广度）的数字，再来判断大小关系。

#include <iostream> #include <vector> using namespace std; class Solution { vector<int> res; public: void Tra(TreeNode* root, int count) { if(root == NULL)return; if(res.size() < count +1) res.push_back(root->val); else{ if(root->val > res[count]) res[count] = root->val; } Tra(root->left,count+1); Tra(root->right,count+1); //return res; } vector<int> largestValues(TreeNode* root) { if(root == NULL)return res; Tra(root,0); return res; } };