661. Image Smoother

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) = 0For the point (0,1), (1,0), (1,2), (2,1): floor(5/6) = floor(0.83333333) = 0For the point (1,1): floor(8/9) = floor(0.88888889) = 0

Note:

1. The value in the given matrix is in the range of [0, 255].
2. The length and width of the given matrix are in the range of [1, 150].

class Solution {    public int[][] imageSmoother(int[][] M) {         int[][] ave = new int[M.length][M[0].length];        for (int i = 0; i < M.length; i++) {            for (int j = 0; j < M[i].length; j++) {                int count =0;                if(j>0){                    ave[i][j]+=M[i][j-1];                    count++;                }                if(j<M[i].length-1){                    ave[i][j]+=M[i][j+1];                    count++;                }                if(i>0){                    ave[i][j]+=M[i-1][j];                    count++;                    if(j>0){                        ave[i][j]+=M[i-1][j-1];                        count++;                    }                    if(j<M[i].length-1){                        ave[i][j]+=M[i-1][j+1];                        count++;                    }                }                if(i<M.length-1){                    ave[i][j]+=M[i+1][j];                    count++;                    if(j>0){                        ave[i][j]+=M[i+1][j-1];                        count++;                    }                    if(j<M[i].length-1){                        ave[i][j]+=M[i+1][j+1];                        count++;                    }                }                ave[i][j]+=M[i][j];                count++;                ave[i][j]/=count;            }        }        return ave;    }}