Approach #1: Iterate Through Grid

Intuition and Algorithm

For each cell in the grid, look at the immediate neighbors - up to 9 of them, including the original cell.

Then, we will add the sum of the neighbors into ans[r][c] while recording count, the number of such neighbors. The final answer is the sum divided by the count.

Complexity Analysis

  • Time Complexity: , where is the number of pixels in our image. We iterate over every pixel.

  • Space Complexity: , the size of our answer.


Analysis written by: @awice.