<p>Given an <code>n x n</code> binary matrix <code>grid</code>, return <em>the length of the shortest <strong>clear path</strong> in the matrix</em>. If there is no clear path, return <code>-1</code>.</p>

<p>A <strong>clear path</strong> in a binary matrix is a path from the <strong>top-left</strong> cell (i.e., <code>(0, 0)</code>) to the <strong>bottom-right</strong> cell (i.e., <code>(n - 1, n - 1)</code>) such that:</p>

<ul>
	<li>All the visited cells of the path are <code>0</code>.</li>
	<li>All the adjacent cells of the path are <strong>8-directionally</strong> connected (i.e., they are different and they share an edge or a corner).</li>
</ul>

<p>The <strong>length of a clear path</strong> is the number of visited cells of this path.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/18/example1_1.png" style="width: 500px; height: 234px;" />
<pre>
<strong>Input:</strong> grid = [[0,1],[1,0]]
<strong>Output:</strong> 2
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/18/example2_1.png" style="height: 216px; width: 500px;" />
<pre>
<strong>Input:</strong> grid = [[0,0,0],[1,1,0],[1,1,0]]
<strong>Output:</strong> 4
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> grid = [[1,0,0],[1,1,0],[1,1,0]]
<strong>Output:</strong> -1
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>n == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= n &lt;= 100</code></li>
	<li><code>grid[i][j] is 0 or 1</code></li>
</ul>

class Solution {
public:
    int shortestPathBinaryMatrix(vector<vector<int>>& grid) {
        queue<vector<int>> qu;
        qu.push({0,0,1});
        vector<pair<int, int>> directions {{0,1},{0,-1},{1,0},{-1,0},{1,1},{-1,-1},{-1,1},{1,-1}};
        while (!qu.empty()) {
            auto& node = qu.front();
            int row = node.at(0), col = node.at(1), dist = node.at(2);
            qu.pop();
            if (grid[row][col] == 1) {
                continue;
            }
            if (row == grid.size() - 1 && col == grid.front().size() - 1) {
                return dist;
            }
            grid[row][col] = 1;
            for (auto [row_del, col_del] : directions) {
                if (IsValid(grid, row + row_del, col + col_del)) {
                    qu.push({row + row_del, col + col_del, dist + 1});
                }
            }
        }
        return -1;
    }
private:
    bool IsValid(const vector<vector<int>>& grid, int row, int col) {
        if (row < 0 || col < 0 || row >= grid.size() || col >= grid.front().size() || grid.at(row).at(col) == 1) {
            return false;
        }
        return true;
    }
};
59200