Provided a 2D matrix of 0 and 1, check if triangle can be formed using continuous 1's.
If possible return it's perimeter. Otherwise return -1

eg.
0 0 0 0 1
0 0 0 1 1
0 0 1 1 1
0 1 1 1 1

Perimeter in this case is 9.

Can someone help me with the solution of this? I just can't understand this problem