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) = 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:

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].

解题思路：

暂时想不到好办法。。用最蠢的M*N*8算了。

class Solution {
public:
    vector<vector<int>> imageSmoother(vector<vector<int>>& M) {
        if(M.size()==0) return M;
        vector<vector<int>> ret = M;
        vector<vector<int>> store;
        for(int i=0;i<M.size();i++)
            for(int j=0;j<M[0].size();j++)
                ret[i][j]=0;

        for(int i=0;i<M.size();i++){
            for(int j=0;j<M[0].size();j++){
            int sum=0;
            int count=0;
                sum+=M[i][j];count++;
                if(j-1>=0) {sum+=M[i][j-1];count++;}
                if(j+1<M[0].size()) {sum+=M[i][j+1];count++;}

                if(i-1>=0){
                sum+=M[i-1][j];count++;
                if(j-1>=0) {sum+=M[i-1][j-1];count++;}
                if(j+1<M[0].size()) {sum+=M[i-1][j+1];count++;}

                }
                if(i+1<M.size()){
                sum+=M[i+1][j];count++;
                if(j-1>=0) {sum+=M[i+1][j-1];count++;}
                if(j+1<M[0].size()) {sum+=M[i+1][j+1];count++;}

                }
                ret[i][j]= sum/count;

            }
        }


        return ret;

    }
};