You are trying to drive from the top left of a city to the bottom right corner.
Your car can only move to directly to the right or directly down.
The city roads are stored in a 2d matrix of size m*n.
The values at grid[i][j] represent the time when that traffic light will turn green (meaning you can access that position).
Return the earliest time you can reach the bottom right corner.
[
[1, 2, 3, 4],
[2, 2, 2, 1],
[4, 3, 5, 2]
]
result = 2
[
[1, 1, 1, 9],
[9, 9, 1, 9],
[1, 1, 1, 9],
[1, 9, 9, 9],
[1, 1, 1, 1]
]
result = 1
Approach
This approach requires a set to store visited paths, otherwise it becomes combinatorial to solve the problem.