You have gone fishing in the river. The river is located to the right of the buildings. There are

$$n$$ buildings in a line.

You are given an integer array of heights of size n that represents the heights of the buildings

in the line.

A building has a river view if the building can see the river without obstructions. Formally, a

building has a river view if all the buildings to its right have a smaller height.

Return a list of indices $(0-$indexed$)$ of buildings that have a river view, sorted in increasing

order.

Requirements

$1.$ Implement the above problem statement using Stacks.

$2.$ Analyze the time complexity of your algorithm.

$3.$ Implement the above problem statement using Python $3\mathrm{.}7.$

$4.$ Make sure proper exception handling is written for the code.

Sample Input

Input should be taken in through a file called $$inputPS$01.$txt$$ which has the fixed format

as below: