I tried to solve the KCHAR.
Link to the Question : KCHAR
Link to my solution : link
Although my solution is giving correct answer for all test cases I have tried, it’s still showing WA.
Please provide some test cases where it might be failing.
Thank you 
Your code fails for this
1
6
Expected output:a
Your output:c
But the answer is not a. As the string given in question also contains c at 6th position. S3 = “aacaacc”
Your solution got AC when i submitted in practice link. Please re-check 
I have already wasted my 20 minutes finding where the mistake is, now i am reading ur comment :(…
I am in a worse state than you 