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.
Note: A leaf is a node with no children.
Example:
Given binary tree [3,9,20,null,null,15,7],
return its depth = 3.
Solution:
#include <iostream>
using namespace std;
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;
return max( maxDepth( root->right), maxDepth( root->left)) + 1;
}
};
总结: 用了递归的思想。