Hi! I encounter difficulties in finding a solution to this problem: having a matrix filled with 0 and 1, size N x N with N <= 1000, output the number of squares with the border filled with 1 (we are not interested in what's inside the square). We consider valid even the squares of size 1x1. For this example, the answer is 27. Can anybody help me? 0000000 0111100 0101111 0100101 0111111 0000011 0000011