leetcode

Leetcode problem solutions
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1861-rotating-the-box.rs (3063B)

      1/// 1861. Rotating the Box (Medium)
      2///
      3/// You are given an m x n matrix of characters box representing a side-view of
      4/// a box. Each cell of the box is one of the following:
      5///
      6///   * A stone '#'
      7///   * A stationary obstacle '*'
      8///   * Empty '.'
      9///
     10/// The box is rotated *90 degrees clockwise*, causing some of the stones to
     11/// fall due to gravity. Each stone falls down until it lands on an obstacle,
     12/// another stone, or the bottom of the box. Gravity *does not* affect the
     13/// obstacles' positions, and the inertia from the box's rotation *does not
     14/// *affect the stones' horizontal positions.
     15///
     16/// It is *guaranteed* that each stone in box rests on an obstacle, another
     17/// stone, or the bottom of the box.
     18///
     19/// Return an n x m matrix representing the box after the rotation described
     20/// above.
     21///
     22/// *Example 1:*
     23///
     24///   *Input:* box = [["#",".","#"]]
     25///   *Output:* [["."],
     26///            ["#"],
     27///            ["#"]]
     28///
     29/// *Example 2:*
     30///
     31///   *Input:* box = [["#",".","*","."],
     32///                 ["#","#","*","."]]
     33///   *Output:* [["#","."],
     34///            ["#","#"],
     35///            ["*","*"],
     36///            [".","."]]
     37///
     38/// *Example 3:*
     39///
     40///   *Input:* box = [["#","#","*",".","*","."],
     41///                 ["#","#","#","*",".","."],
     42///                 ["#","#","#",".","#","."]]
     43///   *Output:* [[".","#","#"],
     44///            [".","#","#"],
     45///            ["#","#","*"],
     46///            ["#","*","."],
     47///            ["#",".","*"],
     48///            ["#",".","."]]
     49///
     50/// *Constraints:*
     51///
     52///   * m == box.length
     53///   * n == box[i].length
     54///   * 1 <= m, n <= 500
     55///   * box[i][j] is either '#', '*', or '.'.
     56///
     57use leetcode::*;
     58
     59struct Solution {}
     60
     61impl Solution {
     62    pub fn rotate_the_box(in_box: Vec<Vec<char>>) -> Vec<Vec<char>> {
     63        let n = in_box.len();
     64        let m = in_box[0].len();
     65        let mut out_box = vec![vec!['.'; n]; m];
     66        for x in (0..n).rev() {
     67            let mut last = m - 1;
     68            for y in (0..m).rev() {
     69                let c = in_box[n - 1 - x][y];
     70                if c == '*' {
     71                    out_box[y][x] = '*';
     72                    if y > 0 {
     73                        last = y - 1;
     74                    }
     75                } else if c == '#' {
     76                    out_box[last][x] = '#';
     77                    last = last.saturating_sub(1);
     78                }
     79            }
     80        }
     81        out_box
     82    }
     83}
     84
     85pub fn main() {
     86    println!("{:?}", Solution::rotate_the_box(arg_into(1)));
     87}
     88
     89#[cfg(test)]
     90mod tests {
     91    use crate::Solution;
     92    use leetcode::vvc;
     93
     94    #[test]
     95    fn test() {
     96        assert_eq!(
     97            Solution::rotate_the_box(vvc("[[#,.,#]]")),
     98            vvc("[[.],[#],[#]]")
     99        );
    100        assert_eq!(
    101            Solution::rotate_the_box(vvc("[[#,.,*,.],[#,#,*,.]]")),
    102            vvc("[[#,.],[#,#],[*,*],[.,.]]")
    103        );
    104        assert_eq!(
    105            Solution::rotate_the_box(vvc("[[#,#,*,.,*,.],[#,#,#,*,.,.],[#,#,#,.,#,.]]")),
    106            vvc("[[.,#,#],[.,#,#],[#,#,*],[#,*,.],[#,.,*],[#,.,.]]")
    107        )
    108    }
    109}