661. Image Smoother
1. Description
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.
2. Example
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
3. 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].
4. Solutions
My Accepted Solution
n is the number of grids in i_image
Time complexity: O(n)
Space complexity: O(n)
class Solution
{
private:
int getAverageNode(vector<vector<int>> &i_image, int row, int colum)
{
int result = 0, nodeCount = 0;
for(int i = row - 1; i <= row + 1; i++)
{
for(int j = colum - 1; j <= colum + 1; j++)
{
if(0 <= i && i < i_image.size() && 0 <= j && j < i_image.front().size())
{
nodeCount++;
result += i_image[i][j];
}
}
}
return (result / nodeCount);
}
public:
// vector<vector<int>> imageSmoother(vector<vector<int>>& M)
vector<vector<int>> imageSmoother(vector<vector<int>> &i_image)
{
vector<vector<int>> result(i_image.size(), vector<int>(i_image.front().size()));
for(int i = 0; i < i_image.size(); i++)
{
for(int j = 0; j < i_image.front().size(); j++)
{
result[i][j] = getAverageNode(i_image, i, j);
}
}
return result;
}
};