Rotating the Box
You are given an m x n matrix of characters boxGrid representing a side-view of a box. Each cell of the box is one of the following:
- A stone
'#' - A stationary obstacle
'*' - Empty
'.'
The box is rotated 90 degrees clockwise, causing some of the stones to fall due to gravity. Each stone falls down until it lands on an obstacle, another stone, or the bottom of the box. Gravity does not affect the obstacles' positions, and the inertia from the box's rotation does not affect the stones' horizontal positions.
It is guaranteed that each stone in boxGrid rests on an obstacle, another stone, or the bottom of the box.
Return an n x m matrix representing the box after the rotation described above.
Example 1
# . #
Input
boxGrid = [["#",".","#"]]Output
[["."],["#"],["#"]]After rotating the single row clockwise, the stones fall to occupy the lower two cells of the resulting column.
Example 2
# . * . # # * .
Input
boxGrid = [["#",".","*","."],["#","#","*","."]]Output
[["#","."],["#","#"],["*","*"],[".","."]]After rotation, stones settle downward while the obstacles remain in their rotated positions.
Constraints
- m == boxGrid.length
- n == boxGrid[i].length
- 1 <= m, n <= 500
- boxGrid[i][j] is either '#', '*', or '.'.