N QUEEN HARD tle

[ann8497 (Ankit Mittal)]

https://ide.codingblocks.com/s/53556
getting tle in 3 test cases
question link - https://online.codingblocks.com/player/10856/content/5151

[Anubhav-Aron-1353657628083250 (Anubhav Aron)]

N-Queen using Bitsets + Backtracking