ImageSmoother.java

package array;
/**
 * Created by gouthamvidyapradhan on 17/02/2018.
 *  * 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 ImageSmoother {

    int[] R = {1, -1, 0, 0, 1, -1, 1, -1};
    int[] C = {0, 0, -1, 1, 1, 1, -1, -1};
    public static void main(String[] args) throws Exception{

    }

    public int[][] imageSmoother(int[][] M) {
        int[][] result = new int[M.length][M[0].length];
        for(int i = 0; i < M.length; i ++){
            for(int j = 0; j < M[0].length; j ++){
                int numCount = 0;
                int totalCount = 1;
                for(int k = 0; k < 8; k++){
                    int newR = i + R[k];
                    int newC = j + C[k];
                    if(newR >= 0 && newC >= 0 && newR < M.length && newC < M[0].length){
                        if(M[newR][newC] > 0){
                            numCount += M[newR][newC];
                        }
                        totalCount++;
                    }
                }
                if(M[i][j] == 1) numCount++;
                result[i][j] = numCount / totalCount;
            }
        }
        return result;
    }

}