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.
思路:遞歸。二叉樹最大深度經典結論,左右分別遞歸下去,每層深度加1,求最大值。
/**
* 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) return 0;
return max(maxDepth(root->left),maxDepth(root->right))+1;
}
};