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1975-maximum-matrix-sum.rs (2119B)

      1/// 1975. Maximum Matrix Sum (Medium)
      2///
      3/// You are given an n x n integer matrix. You can do the following operation
      4/// *any* number of times:
      5///
      6///   * Choose any two *adjacent* elements of matrix and *multiply* each of them
      7///   by -1.
      8///
      9/// Two elements are considered *adjacent* if and only if they share a *border*.
     10///
     11/// Your goal is to *maximize* the summation of the matrix's elements. Return
     12/// the *maximum* sum of the matrix's elements using the operation mentioned
     13/// above.
     14///
     15/// *Example 1:*
     16///
     17///   *Input:* matrix = [[1,-1],[-1,1]]
     18///   *Output:* 4
     19///   Explanation: We can follow the following steps to reach sum equals 4:
     20///   - Multiply the 2 elements in the first row by -1.
     21///   - Multiply the 2 elements in the first column by -1.
     22///
     23/// *Example 2:*
     24///
     25///   *Input:* matrix = [[1,2,3],[-1,-2,-3],[1,2,3]]
     26///   *Output:* 16
     27///   Explanation: We can follow the following step to reach sum equals 16:
     28///   - Multiply the 2 last elements in the second row by -1.
     29///
     30/// *Constraints:*
     31///
     32///   * n == matrix.length == matrix[i].length
     33///   * 2 <= n <= 250
     34///   * -105 <= matrix[i][j] <= 105
     35///
     36use leetcode::*;
     37
     38struct Solution {}
     39
     40impl Solution {
     41    pub fn max_matrix_sum(matrix: Vec<Vec<i32>>) -> i64 {
     42        let mut min = i32::MAX;
     43        let mut count = 0usize;
     44        let mut sum = 0i64;
     45        let mut zero = false;
     46        for row in matrix {
     47            for entry in row {
     48                sum += entry.abs() as i64;
     49                min = min.min(entry.abs());
     50                zero |= entry == 0;
     51                count += (entry < 0) as usize;
     52            }
     53        }
     54        if !zero && count % 2 == 1 {
     55            sum -= 2 * min as i64;
     56        }
     57        sum
     58    }
     59}
     60
     61pub fn main() {
     62    println!("{:?}", Solution::max_matrix_sum(arg_into(1)));
     63}
     64
     65#[cfg(test)]
     66mod tests {
     67    use crate::Solution;
     68    use leetcode::vvi;
     69
     70    #[test]
     71    fn test() {
     72        assert_eq!(Solution::max_matrix_sum(vvi("[[1,-1],[-1,1]]")), 4);
     73        assert_eq!(
     74            Solution::max_matrix_sum(vvi("[[1,2,3],[-1,-2,-3],[1,2,3]]")),
     75            16
     76        );
     77    }
     78}