Please help to track my mistake

#1

here is my code
I have used the contest sequence type approach in this question
and the test cases I can come up with this question it is passing all of that.
please check where I have mistaken
thank you

#2

hey, first of all this is a greedy question,
& sorting needs to be done on the basis of least ending time

in the custom sort function

return a.second < b.second

I have added code, which uses greedy approach to select maximum activities