<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>

from queue import Queue

class Solution:
    def getNextCells(self, i, j, gridValue):
        nextCells = []

        if gridValue == 1:
            nextCells.append([i, j-1])
            nextCells.append([i, j+1])
        
        if gridValue == 2:
            nextCells.append([i-1, j])
            nextCells.append([i+1, j])

        if gridValue == 3:
            nextCells.append([i, j-1])
            nextCells.append([i+1, j])

        if gridValue == 4:
            nextCells.append([i, j+1])
            nextCells.append([i+1, j])

        if gridValue == 5:
            nextCells.append([i-1, j])
            nextCells.append([i, j-1])

        if gridValue == 6:
            nextCells.append([i-1, j])
            nextCells.append([i, j+1])

        return nextCells
    
    def getNextValidCells(self, i, j, grid, n, m)  -> List:
        # Checks if the adjacent cells can be connected by roads
        # Returns 0-2 cells
        nextCells = self.getNextCells(i, j, grid[i][j])

        nextValidCells = []

        # Check if the roads are connected
        for cell in nextCells:
            i2 = cell[0]
            j2 = cell[1]
            if self.isValidCell(i2, j2, n, m):
                nextCells2 = self.getNextCells(i2, j2, grid[i2][j2])

                for cell2 in nextCells2:
                    if cell2[0] == i and cell2[1] == j:
                        nextValidCells.append(cell)

        return nextValidCells

    def isValidCell(self, i, j, n, m):
        if 0 <= i and i < n and 0 <= j and j < m:
            return True
        return False

    def hasValidPath(self, grid: List[List[int]]) -> bool:
        """
        :type grid: List[List[int]]
        :rtype: bool
        """
        n = len(grid)
        m = len(grid[0])
        visited = [[0 for _ in range(m)] for _ in range(n)] 

        # Create a queue
        q = Queue()
        q.put([0, 0])

        while q.qsize() > 0:
            current = q.get()
            i = current[0]
            j = current[1]
            visited[i][j] = True

            # Go to the next connected cell (Not visited)
            nextValidCells = self.getNextValidCells(i, j, grid, n, m)

            for cell in nextValidCells:
                if visited[cell[0]][cell[1]] == False:
                    q.put(cell)
            
        if visited[n-1][m - 1]:
            return True
        return False
        
19643