Title

the problem link

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].

题目大意:给个二维数组，平滑每个元素

Solution

//cpp:
class Solution {
public:
	vector<vector<int>> imageSmoother(vector<vector<int>>& M) {
		int R = M.size();
		int C = M[0].size();
		vector<vector<int>> M1(R);
		for (int i = 0; i < R; i++)
			M1[i].resize(C);
		for (int r = 0; r < R; r++) {
			for (int c = 0; c < C; c++) {
				int count = 0;
				for (int nr = r - 1; nr <= r + 1; nr++) {
					for (int nc = c - 1; nc <= c + 1; nc++) {
						if (0 <= nr && nr < R && 0 <= nc&&nc < C) {
							M1[r][c] += M[nr][nc];
							count++;
						}
					}
				}
				M1[r][c] /= count;
			}
		}
		return M1;
	}
};