You are given an n x n grid where we place some 1 x 1 x 1 cubes that are axis-aligned with the x, y, and z axes.Each value v = grid[i][j] represents a tower of v cubes placed on top of the cell (i, j).We view the projection of these cubes onto the xy, yz, and zx planes.A projection is like a shadow, that maps our 3-dimensional figure to a 2-dimensional plane. We are viewing the “shadow” when looking at the cubes from the top, the front, and the side.Return the total area of all three projections.
class Solution: # Time: O(n^2) over the grid cells # Space: O(1) extra beyond the input def projection_area(self, grid: list[list[int]]) -> int: top = sum(1 for row in grid for cube in row if cube > 0) front = sum(max(row) for row in grid) side = sum(max(col) for col in zip(*grid, strict=True)) return top + front + side
