README.md

861. Score After Flipping Matrix

We have a two dimensional matrix A where each value is 0 or 1.

A move consists of choosing any row or column, and toggling each value in that row or column: changing all 0s to 1s, and all 1s to 0s.

After making any number of moves, every row of this matrix is interpreted as a binary number, and the score of the matrix is the sum of these numbers.

Return the highest possible score.

Example 1:

Input: [[0,0,1,1],[1,0,1,0],[1,1,0,0]]
Output: 39
Explanation:
Toggled to [[1,1,1,1],[1,0,0,1],[1,1,1,1]].
0b1111 + 0b1001 + 0b1111 = 15 + 9 + 15 = 39

Note:

1. 1 <= A.length <= 20
2. 1 <= A[0].length <= 20
3. A[i][j] is 0 or 1.

Solutions (Rust)

1. Greedy

impl Solution {
    pub fn matrix_score(a: Vec<Vec<i32>>) -> i32 {
        let m = a.len();
        let n = a[0].len();
        let mut ret = 0;

        for c in 0..n {
            let mut zeros = 0;

            for r in 0..m {
                zeros += a[r][0] ^ a[r][c];
            }

            ret += zeros.max(m as i32 - zeros) * (1 << (a[0].len() - 1 - c));
        }

        ret
    }
}