#923 · #1861 · Rotating the Box(旋转盒子)

Given an m x n box represented by a grid of characters, where # is a stone, * is a fixed obstacle and . is empty, rotate the box 90 degrees clockwise so that it becomes n x m, then let gravity pull every stone down until it rests on the floor or on an obstacle. Return the resulting grid. Constraints: 1 <= m, n <= 500, and each cell is one of #, *, ..