Flip Columns For Maximum Number of Equal Rows — LeetCode 1072 Python Solution

The problem

You are given an m x n binary matrix matrix. You can choose any number of columns in the matrix and flip every cell in that column (i.e., Change the value of the cell from 0 to 1 or vice versa).

Example

Input

matrix = [[0,1],[1,1]]

Output

1

Explanation

After flipping no values, 1 row has all values equal.

Python solution

class Solution:
    def maxEqualRowsAfterFlips(self, matrix: List[List[int]]) -> int:
        cnt = Counter()
        for row in matrix:
            t = tuple(row) if row[0] == 0 else tuple(x ^ 1 for x in row)
            cnt[t] += 1
        return max(cnt.values())

Complexity

Pattern: Matrix and Grid

Treat a 2-D grid as a graph whose neighbours are the four adjacent cells. LeetCode 1072. Flip Columns For Maximum Number of Equal Rows is filed here because LeetCode tags it Matrix, which is the vocabulary this hub collects.

The matrix and grid guide has the Python template for the pattern and the 216 LeetCode problems that use it.

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