InterviewBit Problems   Count Permutations of BST : Unsolved

About the Count Permutations of BST : Unsolved category (1)
The input is wrong , A 3 2 B ? what needs to be done here? (1)
Ques description (3)
Input not given properly (3)
Solution has passed all the test cases but still not getting submitted (2)
Driver program for calling the given method is broken (1)
Not working on interviewbit but works on local (1)
Testcase A:3 and B:1 (2)
Judge seems to be broken (4)
Can somebody explain to me what choose (x+y, y) is doing? (2)
Issue in scanning with predefined testcases (1)
Input scan issue (1)
Issue with the judge system (1)
There is an error in the scanning of input (1)
Count Permutations of BST: fail on correctness (1)