Magnets

Magnets is a puzzle taking place on a grid divided into vertical and horizontal 2x1 rectangles. Some of the rectangles are magnets (with a positive and a negative pole) and some are blank. Numbers to the top and to the left of the grid indicate how many positive poles are in a given column or row, and likewise with numbers to the right/bottom of the grid for negative poles. No two poles of the same sign may be orthogonally adjacent.