Code: Help on Optimization, approach and readability

Question

Hi all

Below is my code:
https://code.sololearn.com/c3SJxe7tnAWg/#cpp

Problem description, sample input and output is present in code as comment.

I need your help to suggest on
-->approach to problem
-->time complexicity
--> code readability
--> any other point

Thanks for your help... I feel that this problem can be handled better than what I have done...Suggestions are welcome.