ENO

You have been given a long type array/list 'arr’ of size 'n’.

It represents an elevation map wherein 'arr[i]’ denotes the elevation of the 'ith' bar.

Print the total amount of rainwater that can be trapped in these elevations.

Note :

The width of each bar is the same and is equal to 1.

Example:

Input: ‘n’ = 6, ‘arr’ = [3, 0, 0, 2, 0, 4].

Output: 10

Explanation: Refer to the image for better comprehension:

Note :

You don't need to print anything. It has already been taken care of. Just implement the given function.

Given an array ‘A’ of size ‘N’, sorted in non-decreasing order. Return the pair of two distinct indices whose value adds up to the given ‘target’. The given array is 0 indexed. So returned indices are in the range [0, N-1], both inclusive. If there are multiple answers, you can return any.

For example:

Suppose ‘N’ = 5, ‘A’ = [1,2,3,4,5], and target = 8
As target == A[2] + A[4] = 3 + 5 = 8.
Hence output will be 2 4.

You're given an alphabetical string ‘S’.

Determine whether it is palindrome or not. A palindrome is a string that is equal to itself upon reversing it.

For example:

‘S’ = racecar
The reverse of ‘S’ is: racecar
Since ‘S’ is equal to its reverse. So ‘S’ is a palindrome.
Hence output will be 1.