I need help with this Problem Traffic Lights.** CSES Problem Set** under Sorting and Searching. I thought of an approach that

-> create a set add elements at every step,

-> Traverse the set and take the difference and take the maximum out of it.

-> display maximum at every step.

But I think this is a very naive approach and Time Complexity would be O(n^2) and n can be up to 10^5, so most of my Test Cases are giving TLE.

I am not able to think of another approach. Can Anyone give me a hint, how should I approach it.