<p>You are given an <code>m x n</code> <code>grid</code>. Each cell of <code>grid</code> represents a street. The street of <code>grid[i][j]</code> can be:</p>

<ul>
	<li><code>1</code> which means a street connecting the left cell and the right cell.</li>
	<li><code>2</code> which means a street connecting the upper cell and the lower cell.</li>
	<li><code>3</code> which means a street connecting the left cell and the lower cell.</li>
	<li><code>4</code> which means a street connecting the right cell and the lower cell.</li>
	<li><code>5</code> which means a street connecting the left cell and the upper cell.</li>
	<li><code>6</code> which means a street connecting the right cell and the upper cell.</li>
</ul>
<img alt="" src="https://assets.leetcode.com/uploads/2020/03/05/main.png" style="width: 450px; height: 708px;" />
<p>You will initially start at the street of the upper-left cell <code>(0, 0)</code>. A valid path in the grid is a path that starts from the upper left cell <code>(0, 0)</code> and ends at the bottom-right cell <code>(m - 1, n - 1)</code>. <strong>The path should only follow the streets</strong>.</p>

<p><strong>Notice</strong> that you are <strong>not allowed</strong> to change any street.</p>

<p>Return <code>true</code><em> if there is a valid path in the grid or </em><code>false</code><em> otherwise</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/03/05/e1.png" style="width: 455px; height: 311px;" />
<pre>
<strong>Input:</strong> grid = [[2,4,3],[6,5,2]]
<strong>Output:</strong> true
<strong>Explanation:</strong> As shown you can start at cell (0, 0) and visit all the cells of the grid to reach (m - 1, n - 1).
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/03/05/e2.png" style="width: 455px; height: 293px;" />
<pre>
<strong>Input:</strong> grid = [[1,2,1],[1,2,1]]
<strong>Output:</strong> false
<strong>Explanation:</strong> As shown you the street at cell (0, 0) is not connected with any street of any other cell and you will get stuck at cell (0, 0)
</pre>

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

<pre>
<strong>Input:</strong> grid = [[1,1,2]]
<strong>Output:</strong> false
<strong>Explanation:</strong> You will get stuck at cell (0, 1) and you cannot reach cell (0, 2).
</pre>

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

<ul>
	<li><code>m == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 300</code></li>
	<li><code>1 &lt;= grid[i][j] &lt;= 6</code></li>
</ul>

class Solution {
public:
    bool bfs(vector<vector<int>>& g,int r,int c,vector<vector<bool>>&vi){
        vector<vector<pair<int,int>>>dirr(7);
        dirr[1] = {{0,-1},{0,1}};
        dirr[2] = {{-1,0},{1,0}};
        dirr[3] = {{0,-1},{1,0}};
        dirr[4] = {{0,1},{1,0}};
        dirr[5] = {{0,-1},{-1,0}};
        dirr[6] = {{0,1},{-1,0}};
        queue<pair<int,int>>q;
        q.push({r,c});
        vi[r][c]=true;
        while(!q.empty()){
            int sz=q.size();
            while(sz--){
                int x = q.front().first;
                int y = q.front().second;
                q.pop();
                
                if(x==g.size()-1 && y==g[0].size()-1) return true;
                
                int type=g[x][y];
                for (int k = 0; k < 2; k++) {
                    int u = x + dirr[type][k].first, v = y + dirr[type][k].second;
                    if (u >= 0 && u < g.size() && v >= 0 && v < g[0].size() && vi[u][v] == false) {
                        vi[u][v] = true;
                        int z=g[u][v];
                        int x1=u+dirr[z][0].first;
                        int y1=v+dirr[z][0].second;
                        int x2=u+dirr[z][1].first;
                        int y2=v+dirr[z][1].second;
                    
                        if((x==x1 && y==y1) || (x==x2 && y==y2))
                            q.push({u,v});
                    }
                }
            }
        }
        return false;
    }
    bool hasValidPath(vector<vector<int>>& grid) {
        int n=grid.size();
        int m=grid[0].size();
        vector<vector<bool>>vis(n,vector<bool>(m,false));
        bool valid = bfs(grid,0,0,vis);
        return valid;
    }
};
56318