Adhoc Problem , but not intuitive

1

Hi I’m struggling on one of the famous problem asked for Microsoft Assessment round. My solution is not working. Please can someone help me for which test case it will Fail.

Problem - link
Problem Statement - pic

My solution -link

Whats wrong in my approach , looks easy and clear still not able to pass all cases

Help me folks

2

What is your problem CE or WA?

3

WA

4

Find the rightmost A and count all B to its left, call that cntB.
Then find the leftmost B and count all A to its right, call that cntA.
ans = min(cntA, cntB)
Works in O(n)
I haven’t verified any corner cases though.

5

Thanks for reply.
This one is not working for all cases.

6

Case1: String only consists of A’s. Delete all B’s.
Case2: String only consists of B’s. Delete all A’s.
Case3: String consists of prefix of A’s of length x. Suffix of B’s n-x. Try for all x.

Answer must be min of 3 cases.

7

There was a similar problem like this one in the April Circuits on Hackerearth.
You can have a look at it.