Leetcode: Maximum Depth of Binary Tree

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.

分析：用递归，一个树的高度等于左子树与右子树高度的最大值加1。

class Solution {
public:
    int maxDepth(TreeNode *root) {
        if(!root) return 0;
        return max(maxDepth(root->left), maxDepth(root->right)) + 1;
    }
};