BST using preorder traversal.cpp

class Solution {
public:
    TreeNode* solve(vector<int>& preorder,int mini,int maxi,int &i){
        if(i>=preorder.size()){
            return NULL;
        }
        if(preorder[i]<mini || preorder[i]>maxi){
            return NULL;
        }
        TreeNode* root=new TreeNode(preorder[i++]);
        root->left=solve(preorder,mini,root->val,i);
        root->right=solve(preorder,root->val,maxi,i);
        return root;
    }
    TreeNode* bstFromPreorder(vector<int>& preorder) {
        int mini=INT_MIN;
        int maxi=INT_MAX;
        int i=0;
        
        return solve(preorder,mini,maxi,i);
    }
};