Reconstruct BST

• Time : O(n)
• Space : O(n)

using namespace std;

// This is an input class. Do not edit.
class BST {
public:
  int value;
  BST *left = nullptr;
  BST *right = nullptr;

  BST(int value) { this->value = value; }
};

BST* helper(vector<int>& A, int& pos, int mi, int ma) {
	if(pos == A.size()) return nullptr;
	if(mi <= A[pos] and A[pos] < ma) {
		BST* bst = new BST(A[pos++]);
		bst->left = helper(A,pos,mi,bst->value);
		bst->right = helper(A,pos,bst->value,ma);
		return bst;
	} else return nullptr;
}

BST *reconstructBst(vector<int> preOrderTraversalValues) {
  int pos = 0;
  return helper(preOrderTraversalValues, pos, INT_MIN, INT_MAX);
}