892. Surface Area of 3D Shapes

On a N * N grid, we place some 1 * 1 * 1 cubes.

Each value v = grid[i][j] represents a tower of v cubes placed on top of grid cell (i, j).

Return the total surface area of the resulting shapes.

Example 1:

Input: [[2]]
Output: 10

Example 2:

Input: [[1,2],[3,4]]
Output: 34

Example 3:

Input: [[1,0],[0,2]]
Output: 16

Example 4:

Input: [[1,1,1],[1,0,1],[1,1,1]]
Output: 32

Example 5:

Input: [[2,2,2],[2,1,2],[2,2,2]]
Output: 46

Note:

• 1 <= N <= 50
• 0 <= grid[i][j] <= 50

class Solution:
    def surfaceArea(self, grid):
        """
        :type grid: List[List[int]]
        :rtype: int
        """
        res = 0
        for i in range(len(grid)):
            for j in range(len(grid)):
                if grid[i][j]:
                    res += grid[i][j]*4+2
                if i:
                    res -= min(grid[i][j],grid[i-1][j])*2
                if j:
                    res -= min(grid[i][j],grid[i][j-1])*2
        return res

这种题啊，不给图就很烦。