Mirror Rows or Columns

Medium

You get a matrix grid of zeros and ones. A row or column is a mirror line if it reads the same in both directions. One flip changes any single cell to the opposite value. Return the minimum number of flips after which **either every row** or **every column** is a mirror line.

Example 1

grid=[[1, 1, 0], [0, 0, 1], [1, 0, 1]] → 2

Making every row a palindrome takes 2 flips (in the first two rows); the columns would also need 2, so the answer is 2.

Example 2

grid=[[0, 1, 1, 0], [1, 1, 0, 0]] → 2

Rows need 2 flips (the second row), columns need 2 too (two columns differ top and bottom). The minimum is 2.

Example 3

grid=[[1], [0], [0]] → 0

Each one-cell row already reads the same both ways.

Constraints

1 ≤ len(grid) · len(grid[0]) ≤ 2 · 10⁵
All rows have the same length
grid[i][j] is 0 or 1

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Topics

Array Two Pointers Matrix

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Input

grid=[[1, 1, 0], [0, 0, 1], [1, 0, 1]]

Expected

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