在二分查找中，我们如何确定答案何时位于下限、上限和中间？

Question

I just started learning Binary search I have understood that when we are finding some exact element we return mid

but in some more advanced questions we have to return lower bounds and upper bounds, how do i identify that? when to return what, I am getting super confused.

Answer 1

In a binary search youre finding a specified number from a SORTED array, so the first entry should be the lower bound and the last the upper bound. so depending on the language it would be something like:

array[0] // lower bound
array[array.length - 1] // upper bound