public class Solution
extends Object
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`.