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###### tags: `Leetcode`

# 104. Maximum Depth of Binary Tree

###### Link : https://leetcode.com/problems/maximum-depth-of-binary-tree/description/

## 題目
回傳二元樹的level
## 程式碼

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int maxDepth(TreeNode* root) {
        if(root == nullptr) return 0;
        return max(maxDepth(root->left) + 1, maxDepth(root->right) + 1);
    }
};