Hitori

Hitori is a Japanese logic puzzle. The goal is to shade squares in a grid so that no number appears more than once in any row or column.

Rules: Colour the neutral cells of the grid black or white. No number may appear more than once on a white cell in any row or column of the grid.
Black cells must not be orthogonally adjacent (but diagonally). All white cells must form a single, orthogonally contiguous area.