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].
public class Solution {
public int[][] ImageSmoother(int[][] M) {
var cx= new int[]{-1,-1,-1, 0, 0, 0, 1, 1, 1};
var cy= new int[]{-1, 0, 1,-1, 0, 1, -1, 0, 1};
var res = new int[M.Length][];
for(int i=0;i<M.Length;i++){
res[i] = new int[M[i].Length];
for(int j=0;j<M[i].Length;j++){
int sum = 0;
int count = 0;
for(int p=0;p<9;p++){
int x = i + cx[p];
int y = j + cy[p];
if(x<0 || x>M.Length-1){
continue;
}
if(y<0 || y>M[i].Length-1){
continue;
}
sum+=M[x][y];
count++;
}
res[i][j]=sum/count;
}
}
return res;
}
}Time Complexity: O(n*m) Where n and m are rows and columns of the given matrix.
Space Complexity: O(1)
