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：这一题是说求出二叉树的最大深度，很显然我们会想到递归，很容易实现。

/**
 * Definition for binary tree
 * 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 pleft=maxDepth(root->left);
        int pright=maxDepth(root->right);
        return (pleft>pright)?pleft+1:pright+1;
    }
};

注意，不要忘记+1.

python实现：

# Definition for a  binary tree node
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param root, a tree node
    # @return an integer
    def maxDepth(self, root):
        if root==None:
            return 0
        nLeft=self.maxDepth(root.left)
        nRight=self.maxDepth(root.right)
        if nLeft>nRight:
            return nLeft+1
        else:
            return nRight+1