Brief overview:-

The functions upper_bound() and lower_bound() functions are useful when we have data stored in a non-decreasingly sorted format and in a given range in the data structure we want to find out:

1. position of the smallest number just > (greater) a given number
2. position of the smallest number >= (greater than or equal to) a given number

we can use these 2 functions.

upper_bound() :-

• returns an iterator pointing to the element just greater than the given number

lower_bound() :-

• returns an iterator pointing to the element greater than or equal to the given number