Leetcode/leetcode1002.cpp at main · ksaini-web/Leetcode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:

int i =0;

TreeNode* build(vector<int>& preorder , int upperBound){

    if(i== preorder.size() ||preorder[i]>upperBound ){
        return NULL;
    }


    TreeNode* root =new TreeNode(preorder[i]);
    i++;

    root->left = build(preorder,root->val);
    root->right = build(preorder,upperBound);


    return root;


}


    TreeNode* bstFromPreorder(vector<int>& preorder) {

        return build(preorder,INT_MAX);

    }
};