leetcode_題解_Maximum Depth of Binary Tree_簡單題

遞歸函數調用DFS（沒有用顯式棧，居然AC了）

/**
 * 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)
            return 0;
        else if(root->left==NULL && root->right==NULL)
            return 1;
        else
        {
            int ldeep,rdeep;
            ldeep=maxDepth(root->left);
            rdeep=maxDepth(root->right);
            if(ldeep>rdeep)
                return ldeep+1;
            else
                return rdeep+1;
        }
    }
};