Image Smoother.py

'''
Given a 2D integer matrix M representing the gray scale of an image, you need to design a smoother to make the gray scale of each cell becomes the average gray scale (rounding down) of all the 8 surrounding cells and itself. If a cell has less than 8 surrounding cells, then use as many as you can.

Example 1:
Input:
[[1,1,1],
 [1,0,1],
 [1,1,1]]
Output:
[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]]
Explanation:
For the point (0,0), (0,2), (2,0), (2,2): floor(3/4) = floor(0.75) = 0
For the point (0,1), (1,0), (1,2), (2,1): floor(5/6) = floor(0.83333333) = 0
For the point (1,1): floor(8/9) = floor(0.88888889) = 0
Note:
The value in the given matrix is in the range of [0, 255].
The length and width of the given matrix are in the range of [1, 150].
'''


class Solution(object):
    def imageSmoother(self, M):
        """
        :type M: List[List[int]]
        :rtype: List[List[int]]
        """
        
        res = [[0 for j in xrange(len(M[i]))] for i in xrange(len(M))]
            
        for i in xrange(len(res)):
            for j in xrange(len(res[i])):
                total = 0
                count = 0
                for x, y in [(0, 0), (1, 0), (1, 1), (0, 1), (-1, 1), (-1, 0), (-1, -1), (0, -1), (1, -1)]:
                    ii = i + x
                    jj = j + y
                    if 0 <= ii < len(res) and 0 <= jj < len(res[ii]):
                        total += M[ii][jj]
                        count += 1


                res[i][j] = total / count

        return res