1284 - Minimum Number of Flips to Convert Binary Matrix to Zero Matrix.

Hard

Given a m x n binary matrix mat. In one step, you can choose one cell and flip it and all the four neighbors of it if they exist (Flip is changing 1 to 0 and 0 to 1). A pair of cells are called neighbors if they share one edge.

Return the minimum number of steps required to convert mat to a zero matrix or -1 if you cannot.

A binary matrix is a matrix with all cells equal to 0 or 1 only.

A zero matrix is a matrix with all cells equal to 0.

Example 1:

Input: mat = [0,0,0,1]

Output: 3

Explanation: One possible solution is to flip (1, 0) then (0, 1) and finally (1, 1) as shown.

Example 2:

Input: mat = [0]

Output: 0

Explanation: Given matrix is a zero matrix. We do not need to change it.

Example 3:

Input: mat = [1,0,0,1,0,0]

Output: -1

Explanation: Given matrix cannot be a zero matrix.

Constraints:

• m == mat.length

• n == mat[i].length

• 1 <= m, n <= 3

• mat[i][j] is either 0 or 1.