Program to find number of columns flips to get maximum number of equal Rows in Python?

Suppose we have a binary matrix, we can select any number of columns in the given matrix and flip every cell in that column. converting a cell means, inverting the cell value. We have to find the maximum number of rows that have all values equal after some number of flips. So if the matrix is like

The output will be 2. This is because after converting values in the first two columns, the last two rows have equal values.

To solve this, we will follow these steps:

• x := matrix, m := number of rows and n := number of columns and r := 0

• for each element i in x

  • c := 0

  • a := a list for all elements l in i, insert l XOR i

  • for each element j in x

    • if j = i or j = a, then increase c by 1

  • r := max of c and r

• return r

Let us see the following implementation to get better understanding:

Example

 Live Demo

class Solution(object):
   def solve(self, matrix):
      x = matrix
      m = len(matrix)
      n = len(matrix[0] )
      r =0
      for i in x:
         c=0
         a=[l ^ 1 for l in i]
         for j in x:
            if j== i or j ==a:
               c+=1
         r=max(c, r)
      return r

ob = Solution()
matrix = [[0,0,0],
         [0,0,1],
         [1,1,0]]
print(ob.solve(matrix))

Input

[[0,0,0],
[0,0,1],
[1,1,0]]

Output

2

Arnab Chakraborty

Published on 10-Nov-2020 08:29:29