I want to code A. Get together with approach by limiting value of f(t) ? but i cant get through it ? can i use sweep line algorithm.... after limiting value?and how to code it?here is link to question https://codeforces.com/edu/course/2/lesson/6/3/practice/contest/285083/problem/A

You can binary search on the answer, and maintain a segment that everyone can reach. If the segment is non-empty then the value is ok.

i find function to be unimodal so ternary search is most optimal then binary search.

How is the function unimodal?

by general intution plot will be minima type where at local minima there will be minimum time requird for all peoples to collect at place.

still can get more precise

What is your definition of $$$f(t)$$$?

Not understood can you tell briefly about it

Even I amn't able to get this, we know that my valid answer will be between [ xi — vi*t , vi*t + xi ], but how to binary search on this?? Also, the problem states that the absolute error should be less than 1e-6. Can someone tell how to proceed with it??