/// 1861. Rotating the Box (Medium)
///
/// You are given an m x n matrix of characters box 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 box 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:* box = [["#",".","#"]]
///   *Output:* [["."],
///            ["#"],
///            ["#"]]
///
/// *Example 2:*
///
///   *Input:* box = [["#",".","*","."],
///                 ["#","#","*","."]]
///   *Output:* [["#","."],
///            ["#","#"],
///            ["*","*"],
///            [".","."]]
///
/// *Example 3:*
///
///   *Input:* box = [["#","#","*",".","*","."],
///                 ["#","#","#","*",".","."],
///                 ["#","#","#",".","#","."]]
///   *Output:* [[".","#","#"],
///            [".","#","#"],
///            ["#","#","*"],
///            ["#","*","."],
///            ["#",".","*"],
///            ["#",".","."]]
///
/// *Constraints:*
///
///   * m == box.length
///   * n == box[i].length
///   * 1 <= m, n <= 500
///   * box[i][j] is either '#', '*', or '.'.
///
use leetcode::*;

struct Solution {}

impl Solution {
    pub fn rotate_the_box(in_box: Vec<Vec<char>>) -> Vec<Vec<char>> {
        let n = in_box.len();
        let m = in_box[0].len();
        let mut out_box = vec![vec!['.'; n]; m];
        for x in (0..n).rev() {
            let mut last = m - 1;
            for y in (0..m).rev() {
                let c = in_box[n - 1 - x][y];
                if c == '*' {
                    out_box[y][x] = '*';
                    if y > 0 {
                        last = y - 1;
                    }
                } else if c == '#' {
                    out_box[last][x] = '#';
                    last = last.saturating_sub(1);
                }
            }
        }
        out_box
    }
}

pub fn main() {
    println!("{:?}", Solution::rotate_the_box(arg_into(1)));
}

#[cfg(test)]
mod tests {
    use crate::Solution;
    use leetcode::vvc;

    #[test]
    fn test() {
        assert_eq!(
            Solution::rotate_the_box(vvc("[[#,.,#]]")),
            vvc("[[.],[#],[#]]")
        );
        assert_eq!(
            Solution::rotate_the_box(vvc("[[#,.,*,.],[#,#,*,.]]")),
            vvc("[[#,.],[#,#],[*,*],[.,.]]")
        );
        assert_eq!(
            Solution::rotate_the_box(vvc("[[#,#,*,.,*,.],[#,#,#,*,.,.],[#,#,#,.,#,.]]")),
            vvc("[[.,#,#],[.,#,#],[#,#,*],[#,*,.],[#,.,*],[#,.,.]]")
        )
    }
}