At 4:00 i have a doubt in lecture

#1

in upper_bound line…why are we subtracting-1 and then -coins.
will it not work if we directly do -1 or do -coins?

#2

@dipeshpandey2001
int idx=upper_bound(…) -coins
gives you the index of the element which is the upper bound of the current value but we need to take the element less than it so we subtract -1
auto idx=upper_bound(…) gives us a iterator at that position but if we want the index we need to do -coins
and that additional -1 can also be done later after finding the index
if you still have any dout feel free to ask and if clear mark it as resolved and rate my experience

#3

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