SDE - 1

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.

You are given an array consisting of N positive integers, and your task is to sort the array in decreasing order of count of set bits in the binary representation of the integers present in the array.

In other words, you have to modify the array such that an integer with more number of set bits should appear before the integer which has lesser number of set bits in its binary representation.

The number of set bits is nothing but the number of 1s present in the binary representation of the integer. For example, the number of set bits in 5(0101) is equal to 2.

Note :

1. If any two numbers have the same count of set bits, then in the sorted array they will appear in the order in which they appear in the original array. For example, let the array be { 2, 4, 3}, in this case, both 2 and 4 have the same number of set bits so the answer will be {3, 2, 4} and not {3, 4, 2}, because in the original array 2 appears before 4.

2. The array may contain duplicate elements.

You are given a string 'S' containing dots(.) and asterisks(*) only, where the dot represents free spaces, and the asterisk denotes lamps. A lamp can lighten up its own cell as well as its immediate neighboring cells. You need to determine the minimum number of extra lamps that have to be installed at some free spaces in the string so that the whole string will be illuminated i.e. all the indices of the string can have access to the light of some lamp.

Note :

If a lamp is present at index 'I', then it illuminates index 'I' - 1, 'I' and 'I' + 1.

If a lamp is present at index 0, then it illuminates only 0 and 1.

Given that the length of the string is greater than or equal to 2.

If a lamp is present at the last index, then it illuminates the last and the second last index, given that the length of the string is greater than or equal to 2.

The length of each string is guaranteed to be at least 1.

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