leetcode刷题日记——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.

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问题分析：问题比较简单，目的是求二叉数的最大深度。可以采用递归的办法，递归条件是二层之间的高度相差1，因为最终要返回最大深度，因此分别对左右子树分别递归，然后将最终结果返回即可，不过这里没有考虑最优解，留待以后优化。代码如下：

/**
* 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) {
if(root==NULL) return 0;
int left=maxDepth(root->left)+1;
int right=maxDepth(root->right)+1;
return left>right?left:right;

}
};