[LeetCode]#661. Image Smoother

Environment: Python 3.7

Key technique: //

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

Analysis:

Define image size, mask size, and boundary. The location [0,0] value do image smooth by using mask as below. The answer is (1+1+1+0)/4=0.75 and 4 point is out of boundary. We need ignore them.

Solution:

class Solution:
    def imageSmoother(self, M):
        m= len(M)
        n=len(M[0])
        result = [[0]*n for i in range(m)]
        for i in range(m):
            for j in range(n):
                t = 0
                c = 0
                for dx in range(-1,2):
                    for dy in range(-1,2):
                        if 0<=i+dx<m and 0<=j+dy<n:
                            t += M[i+dx][j+dy] 
                            c += 1
                result[i][j] = t//c
        return result

Submitted result:

Reference:

https://leetcode.com/problems/image-smoother/discuss/512983/Python-Straightforward