[LeetCode 302] Smallest Rectangle Enclosing Black Pixels (Hard**)
Animageisrepresentedbyabinarymatrixwith0asawhitepixeland1asablackpixel.Theblackpixelsareconnected,i.e.,thereisonlyoneblackregion.Pixelsareconnectedhorizontallyandvertically.Giventhelocation(x,y)ofoneo