- Difficulty: Medium
- Tags: LeetCode, Medium, Bit Manipulation, Array, Backtracking, Enumeration, Matrix, leetcode-2397, O(m * n + m * C(n, k)), O(m), Bitmasks, Hakmem Item 175
Problem
You are given a 0-indexed m x n
binary matrix matrix
and an integer numSelect
, which denotes the number of distinct columns you must select from matrix
.
Let us consider s = {c1, c2, ...., cnumSelect}
as the set of columns selected by you. A row row
is covered by s
if:
- For each cell
matrix[row][col]
(0 <= col <= n - 1
) wherematrix[row][col] == 1
,col
is present ins
or, - No cell in
row
has a value of1
.
You need to choose numSelect
columns such that the number of rows that are covered is maximized.
Return the maximum number of rows that can be covered by a set of numSelect
columns.
Example 1:
Input: matrix = [[0,0,0],[1,0,1],[0,1,1],[0,0,1]], numSelect = 2 Output: 3 Explanation: One possible way to cover 3 rows is shown in the diagram above. We choose s = {0, 2}. - Row 0 is covered because it has no occurrences of 1. - Row 1 is covered because the columns with value 1, i.e. 0 and 2 are present in s. - Row 2 is not covered because matrix[2][1] == 1 but 1 is not present in s. - Row 3 is covered because matrix[2][2] == 1 and 2 is present in s. Thus, we can cover three rows. Note that s = {1, 2} will also cover 3 rows, but it can be shown that no more than three rows can be covered.
Example 2:
Input: matrix = [[1],[0]], numSelect = 1 Output: 2 Explanation: Selecting the only column will result in both rows being covered since the entire matrix is selected. Therefore, we return 2.
Constraints:
m == matrix.length
n == matrix[i].length
1 <= m, n <= 12
matrix[i][j]
is either0
or1
.1 <= numSelect <= n