Associate Engineer

Ninja Land can be represented as a N * N grid in the XY plane. Each cell of this grid can have a building of some height.

You are given a matrix ‘GRID[][]’ of size ‘N’ * ‘N’, where ‘GRID[i][j]’ gives the height of the building at cell (i, j) in XY plane. Note, building at any cell (i, j) is represented as a cuboid that is an axis aligned with the axis ‘X’, ‘Y’, ‘Z’ and has the dimension 1 * 1 * GRID[i][j] along X, Y, Z-axis respectively.

Ninja views the projection of these buildings onto the XY, YZ, and ZX planes. A projection is like a shadow, that maps a 3-dimensional figure to a 2-dimensional plane. We are viewing the "shadow" when looking from the top, the side, and the front, in XY, YZ, ZX plane respectively.

Your task is to find and return the total area of all three projections. See the example for more clarity.

Note:

 ‘GRID[i][j]’ = 0, if there is no building at cell (i, j).

Example:

Consider the following 2*2 ‘GRID[][]’:
                [1, 2]
                [3, 4]

Its projection in XY, YZ, XZ plane is shown below -: 

Area covered in XY plane is 4, Area covered in YZ plane is 6, Area covered in ZX plane is 7, Thus the total area is 4 + 6 + 7 = 17.

You are given an array/list 'ARR' consisting of N integers, which contains elements only in the range 0 to N - 1. Some of the elements may be repeated in 'ARR'. Your task is to find all such duplicate elements.

Note:

1. All the elements are in the range 0 to N - 1.
2. The elements may not be in sorted order.
3. You can return the duplicate elements in any order.
4. If there are no duplicates present then return an empty array.

They take Introduction and about my family members and about the organization. What are your future goals?