883. Projection area of 3D Shapes

Problem

NxN lattice, stacked with 1x1x1 cubes, grid[i][j] represents the number of cubes stacked on a coordinate grid, and the three-view area is calculated.

Input: [[1,2],[3,4]]
Output:17
Explanation: See

Ideas

For the top view, as long as a lattice has a value, the area value is added 1.
For a front view (facing the x-axis), for an X, the highest grid value in the y-axis direction, which indicates that the x follows the y-axis to see the area values seen in the past.
For a side view (facing the y-axis), for a Y, the highest grid value in the x-axis direction, indicating that Y is looking at the area values seen in the past along the y-axis.
Add up these area values.

Code

class Solution(object):    def projectionArea(self, grid):        """        :type grid: List[List[int]]        :rtype: int        """        s = 0        n = len(grid)        for i in range(n):            best_row = 0            best_col = 0            for j in range(n):                if(grid[i][j] > 0):                    s += 1                best_row = max(best_row, grid[i][j])                best_col = max(best_col, grid[j][i])            s += best_row + best_col        return s

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883. Projection area of 3D Shapes