- Difficulty: Medium
- Tags: LeetCode, Medium, Depth-First Search, Breadth-First Search, Union Find, Array, Matrix, leetcode-1391, O(m * n), O(1), Simulation
Problem
You are given an m x n
grid
. Each cell of grid
represents a street. The street of grid[i][j]
can be:
1
which means a street connecting the left cell and the right cell.2
which means a street connecting the upper cell and the lower cell.3
which means a street connecting the left cell and the lower cell.4
which means a street connecting the right cell and the lower cell.5
which means a street connecting the left cell and the upper cell.6
which means a street connecting the right cell and the upper cell.
You will initially start at the street of the upper-left cell (0, 0)
. A valid path in the grid is a path that starts from the upper left cell (0, 0)
and ends at the bottom-right cell (m - 1, n - 1)
. The path should only follow the streets.
Notice that you are not allowed to change any street.
Return true
if there is a valid path in the grid or false
otherwise.
Example 1:
Input: grid = [[2,4,3],[6,5,2]] Output: true Explanation: As shown you can start at cell (0, 0) and visit all the cells of the grid to reach (m - 1, n - 1).
Example 2:
Input: grid = [[1,2,1],[1,2,1]] Output: false Explanation: 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)
Example 3:
Input: grid = [[1,1,2]] Output: false Explanation: You will get stuck at cell (0, 1) and you cannot reach cell (0, 2).
Constraints:
m == grid.length
n == grid[i].length
1 <= m, n <= 300
1 <= grid[i][j] <= 6