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< p > You are given an < code > n x n< / code > binary grid < code > board< / code > . In each move, you can swap any two rows with each other, or any two columns with each other.< / p >
< p > Return < em > the minimum number of moves to transform the board into a < strong > chessboard board< / strong > < / em > . If the task is impossible, return < code > -1< / code > .< / p >
< p > A < strong > chessboard board< / strong > is a board where no < code > 0< / code > ' s and no < code > 1< / code > ' s are 4-directionally adjacent.< / p >
< p > < / p >
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< p > < strong class = "example" > Example 1:< / strong > < / p >
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< img alt = "" src = "https://assets.leetcode.com/uploads/2021/06/29/chessboard1-grid.jpg" style = "width: 500px; height: 145px;" / >
< pre >
< strong > Input:< / strong > board = [[0,1,1,0],[0,1,1,0],[1,0,0,1],[1,0,0,1]]
< strong > Output:< / strong > 2
< strong > Explanation:< / strong > One potential sequence of moves is shown.
The first move swaps the first and second column.
The second move swaps the second and third row.
< / pre >
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< p > < strong class = "example" > Example 2:< / strong > < / p >
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< img alt = "" src = "https://assets.leetcode.com/uploads/2021/06/29/chessboard2-grid.jpg" style = "width: 164px; height: 165px;" / >
< pre >
< strong > Input:< / strong > board = [[0,1],[1,0]]
< strong > Output:< / strong > 0
< strong > Explanation:< / strong > Also note that the board with 0 in the top left corner, is also a valid chessboard.
< / pre >
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< p > < strong class = "example" > Example 3:< / strong > < / p >
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< img alt = "" src = "https://assets.leetcode.com/uploads/2021/06/29/chessboard3-grid.jpg" style = "width: 164px; height: 165px;" / >
< pre >
< strong > Input:< / strong > board = [[1,0],[1,0]]
< strong > Output:< / strong > -1
< strong > Explanation:< / strong > No matter what sequence of moves you make, you cannot end with a valid chessboard.
< / pre >
< p > < / p >
< p > < strong > Constraints:< / strong > < / p >
< ul >
< li > < code > n == board.length< / code > < / li >
< li > < code > n == board[i].length< / code > < / li >
< li > < code > 2 < = n < = 30< / code > < / li >
< li > < code > board[i][j]< / code > is either < code > 0< / code > or < code > 1< / code > .< / li >
< / ul >
