Leetcode 661 Image Smoother

Leetcode 661 Image Smoother

class Solution {public:    int nineSum(vector<vector<int>>& M,int x,int y)    {        //得到每一个元素周围（包括自己）九个元素的平均值        int r = M.size();        int c = M[0].size();        //自己和周围八个元素与自己坐标之差        int xDiff[9] = {0, 0, 1, 1, 1, 0,-1,-1,-1};        int yDiff[9] = {0,-1,-1, 0, 1, 1, 1, 0,-1};         int sum = 0;        int validNum = 0;//对于四条边这个数不等于9,        for(int i = 0;i < 9;i ++)        {            int xi = x + xDiff[i];            int yi = y + yDiff[i];            if(xi >= 0 && yi >= 0 && xi < r && yi <c)            {                sum += M[xi][yi];                validNum ++;            }        }        return sum / validNum;    }    vector<vector<int>> imageSmoother(vector<vector<int>>& M) {    if(M.empty())        return M;    int r = M.size();    int c = M[0].size();    vector<vector<int>> result(r,vector<int>(c));    for(int i = 0;i < r;i ++)    {        for(int j = 0;j < c;j ++)        {            result[i][j] = nineSum(M,i,j);        }    }    return result;    }};