Leetcode-104 Maximum Depth of Binary Tree

#104  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.

即给定一颗二叉树，求出其最大深度。

题解：采用深度优先搜索DFS

如果根节点为空，则深度为0，返回0，递归的出口

如果根节点不为空，那么深度至少为1，然后我们求他们左右子树的深度

比较左右子树深度值，返回较大的那一个

通过递归调用

class Solution {
public:
     int max(int a,int b)
    {
        if(a>=b)
        return a;
        else
        return b;
    }
    int maxDepth(TreeNode* root) {
        if(root == NULL)
            return 0;
        return 1 + max(maxDepth(root->left), maxDepth(root->right));
    }
};