Minimum Obstacle Removal to Reach Corner

You are given a **0-indexed** 2D integer array `grid` of size `m x n`. Each cell has one of two values: - `0` represents an **empty** cell, - `1` represents an **obstacle** that may be removed. You can move up, down, left, or right from and to an empty cell. Return _the **minimum** number of **obstacles** to **remove** so you can move from the upper left corner _`(0, 0)`_ to the lower right corner _`(m - 1, n - 1)`.   **Example 1:** **Input:** grid = [[0,1,1],[1,1,0],[1,1,0]] **Output:** 2 **Explanation:** We can remove the obstacles at (0, 1) and (0, 2) to create a path from (0, 0) to (2, 2). It can be shown that we need to remove at least 2 obstacles, so we return 2. Note that there may be other ways to remove 2 obstacles to create a path. ``` **Example 2:** **Input:** grid = [[0,1,0,0,0],[0,1,0,1,0],[0,0,0,1,0]] **Output:** 0 **Explanation:** We can move from (0, 0) to (2, 4) without removing any obstacles, so we return 0. ```   **Constraints:** - `m == grid.length` - `n == grid[i].length` - `1 <= m, n <= 105` - `2 <= m * n <= 105` - `grid[i][j]` is either `0` **or** `1`. - `grid[0][0] == grid[m - 1][n - 1] == 0`