Tripod Coral (483)

Shade some cells in the grid. All shaded cells must be orthogonally interconnected. All unshaded cells must be orthogonally connected to the edge of the grid. Shaded cells can never form a 2x2 square. Numbers outside the grid indicate the lengths of all blocks of shaded cells in the corresponding row or column, not necessarily in the given order. Each cell that has exactly three shaded orthogonally adjacent cells is marked with a circle.

Reference: WPC 2016 (65)