谷歌跪 SETI

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感谢楼主，祝好运

加油加油! 谢谢楼主的面经!祝楼主好运~

感谢楼主分享经验。运气真的是会影响发挥，特别如果面试官不怎么跟你互动的话，积极性都会下降。

多谢面筋

想看看~~~~

狗家seti和普通的sde面试一样么？

谢谢楼主的面经！楼主别灰心加油多刷题，争取再面！

感谢楼主的面经！这道题传输的变量比较多和杂，用一个object兜一下或许会方便一些

1. /**
   
2. * Definition for a binary tree node.
   
3. * struct TreeNode {
   
4. *     int val;
   
5. *     TreeNode *left;
   
6. *     TreeNode *right;
   
7. *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
   
8. * };
   
9. */
   
10. class Solution {
    
11. public:
    
12.     struct SubTreeInfo;
    
13.    
    
14.     int largestBSTSubtree(TreeNode* root) {
    
15.         int answer = 0;
    
16.         largestBST_Rec(root, &answer);
    
17.         return answer;
    
18.     }
    
19.    
    
20.     struct SubTreeInfo largestBST_Rec(TreeNode* node, int * answer){
    
21.         if(!node)return SubTreeInfo(true, 0, 0, 0);
    
22.         auto leftTreeInfo = largestBST_Rec(node->left, answer);
    
23.         auto rightTreeInfo = largestBST_Rec(node->right, answer);
    
24.         
    
25.         bool isBST = leftTreeInfo.isBST && rightTreeInfo.isBST;
    
26.         
    
27.         int leftBound = node->val, rightBound = node->val, count = 1;
    
28.         
    
29.         if(node->left){
    
30.             isBST &= (node->val > leftTreeInfo.rightBound);
    
31.             count += leftTreeInfo.count;
    
32.             leftBound = leftTreeInfo.leftBound;
    
33.         }
    
34.         if(node->right){
    
35.             isBST &= (node->val < rightTreeInfo.leftBound);
    
36.             count += rightTreeInfo.count;
    
37.             rightBound = rightTreeInfo.rightBound;
    
38.         }
    
39.         
    
40.         if(isBST)*answer = max(*answer, count);
    
41.         
    
42.         return SubTreeInfo(isBST, leftBound, rightBound, count);
    
43.     }
    
44.    
    
45.     struct SubTreeInfo{
    
46.         bool isBST;
    
47.         int leftBound, rightBound, count;
    
48.         SubTreeInfo(bool isBST_, int leftBound_, int rightBound_, int count_):
    
49.             isBST(isBST_), leftBound(leftBound_), rightBound(rightBound_), count(count_){}
    
50.     };
    
51. };

复制代码

谢谢楼主