Transform to Chessboard
You are given an n x n binary grid board. In each move, you can swap any two rows with each other, or any two columns with each other.
Return the minimum number of moves to transform the board into a chessboard board. If the task is impossible, return -1.
A chessboard board is a board where no 0's and no 1's are 4-directionally adjacent.
Example 1
0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1
Input
board = [[0,1,1,0],[0,1,1,0],[1,0,0,1],[1,0,0,1]]Output
2One potential sequence uses two moves: swap the first and second column, then swap the second and third row.
Example 2
0 1 1 0
Input
board = [[0,1],[1,0]]Output
0The board is already a valid chessboard, including the variant with 0 in the top-left corner.
Constraints
- n == board.length
- n == board[i].length
- 2 <= n <= 30
- board[i][j] is either 0 or 1.