leetcode Maximum Depth of Binary Tree

Maximum Depth of Binary Tree

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Total Accepted: 85301 Total
Submissions: 188185 Difficulty: Easy

Given a binary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

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相当于广度遍历，然后加一个统计深度的变量就好。

/**

* Definition for a binary tree node.

* struct TreeNode {

* int val;

* TreeNode *left;

* TreeNode *right;

* TreeNode(int x) : val(x), left(NULL), right(NULL) {}

* };

*/

class Solution {

public:

int maxDepth(TreeNode* root)

{

int result=0;

vector<TreeNode*> levelNode;

if (root == NULL)

return 0;

int levelNum = 1, nextlevel = 0;

levelNode.push_back(root);

while (!levelNode.empty())

{

result++;

for (int i = 0; i < levelNum; i++)

{

if (levelNode[0]->left != NULL)

{

nextlevel++;

levelNode.push_back(levelNode[0]->left);

}

if (levelNode[0]->right != NULL)

{

levelNode.push_back(levelNode[0]->right);

nextlevel++;

}

levelNode.erase(levelNode.begin());

}

levelNum = nextlevel;

nextlevel = 0;

}

return result;

}

};