Count Square Submatrices

Problem

Given a 2D binary matrix matrix, return the total number of square submatrices that have all ones. This includes squares of any size that are composed entirely of '1's, located anywhere within the matrix.

Examples

countSquares([
  [0,1,1,1],
  [0,1,1,0],
  [0,1,1,0]
])
// returns 9
/* Why? There's 7 squares of size 1
And there's 2 squares of size 2 */