<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:
    void search(vector<vector<int>>& grid, vector<vector<bool>>& visited, vector<vector<int>>& min_dist, int i, int j) {
        list<pair<int, int>> q;
        q.push_back(make_pair(i, j));
        visited[i][j] = true;

        while (!q.empty()) {
            auto& elem = q.front();
            int i = elem.first;
            int j = elem.second;
            visited[i][j] = true;
            q.pop_front();

            bool left = j > 0;
            bool right = j < grid[0].size() - 1;
            bool top = i > 0;
            bool bot = i < grid.size() - 1;

            int d = min_dist[i][j] + 1;

            if (left && grid[i][j-1] == 0 && !visited[i][j-1]) {
                min_dist[i][j-1] = d;
                visited[i][j-1] = true;
                q.emplace_back(make_pair(i, j-1));
            }

            if (right && grid[i][j+1] == 0 && !visited[i][j+1]) {
                min_dist[i][j+1] = d;
                visited[i][j+1] = true;
                q.emplace_back(i, j+1);
            }

            if (top && grid[i-1][j] == 0 && !visited[i-1][j]) {
                min_dist[i-1][j] = d;
                visited[i-1][j] = true;
                q.emplace_back(i-1, j);
            }

            if (bot && grid[i+1][j] == 0 && !visited[i+1][j]) {
                min_dist[i+1][j] = d;
                visited[i+1][j] = true;
                q.emplace_back(i+1, j);
            }

            if(bot && right && grid[i+1][j+1] == 0 && !visited[i+1][j+1]) {
                min_dist[i+1][j+1] = d;
                visited[i+1][j+1] = true;
                q.emplace_back(i+1, j+1);
            }

            if(top && left && grid[i-1][j-1] == 0 && !visited[i-1][j-1]) {
                min_dist[i-1][j-1] = d;
                visited[i-1][j-1] = true;
                q.emplace_back(i-1, j-1);
            }

            if (bot && left && grid[i+1][j-1] == 0 && !visited[i+1][j-1]) {
                min_dist[i+1][j-1] = d;
                visited[i+1][j-1] = true;
                q.emplace_back(i+1, j-1);
            }

            if (top && right && grid[i-1][j+1] == 0 && !visited[i-1][j+1]) {
                min_dist[i-1][j+1] = d;
                visited[i-1][j+1] = true;
                q.emplace_back(i-1, j+1);
            }
        }
    }
    int shortestPathBinaryMatrix(vector<vector<int>>& grid) {
        vector<vector<int>> min_dist(grid.size(), vector<int>(grid[0].size(), -1));
        vector<vector<bool>> visited(grid.size(), vector<bool>(grid[0].size(), false));
        if (grid[0][0] != 0) {
            return -1;
        }
        min_dist[0][0] = 1;
        search(grid, visited, min_dist, 0, 0);
        if (min_dist[grid.size()-1][grid[0].size()-1] == INT_MAX) {
            return -1;
        }
        return min_dist[grid.size()-1][grid[0].size()-1];
    }
};
33666