LeetCode刷题笔记--104. Maximum Depth of Binary Tree

104. Maximum Depth of Binary Tree

Easy

115447FavoriteShare

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],

    3
   / \
  9  20
    /  \
   15   7

return its depth = 3.

这道题在做好最小深度（第111题）后做的，只是改点参数就行了。但是温馨提示：

一定要手打代码！

一定要手打代码！

一定要手打代码！

否则会报错：error: stray ‘\302’ in program

全部手打后错误消失。

下面是AC的代码：

/**
 * 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 look(TreeNode* root, int dist)
    {
        if(root!=NULL)
        {
            dist++;
            if(root->left==NULL&&root->right==NULL)
            {
                return dist;
            }
            return max(look(root->left,dist),look(root->right,dist));//把min改成max
            
        }
        else return 0;//把0x7fffffff改成0
    }
    
    int maxDepth(TreeNode* root) {
        if(root==NULL)return 0;
        int distance=1;
        if(root->left==NULL&&root->right==NULL)return 1;
        return max(look(root->left,1),look(root->right,1));//把min改成max
        
    }
};