方格矩阵连通性求解,一个矩阵，随机打开一个方格（open），如果打开的方格使得矩阵上边和下边连通，即为连通了。平均需要随机打开多少个方格能使得矩阵连通？-Given a composite systems comprised of randomly distributed insulating and metallic materials: what fraction of the materials need to be metallic so that the composite system is an electrical conductor? Given a porous landscape with water on the surface (or oil below), under what conditions will the water be able to drain through to the bottom (or the oil to gush through to the surface)? Scientists have defined an abstract process known as percolation to model such situations.