Closest DashMart

Problem Statement
A DashMart is a warehouse run by DoorDash that houses items found in convenience stores, grocery stores, and restaurants. We have a city with open roads, blocked-off roads, and DashMarts.

City planners want you to identify how far a location is from its closest DashMart.

You can only travel over open roads (up, down, left, right).

Locations are given in [row, col] format.

Example 1
[

0 1 2 3 4 5 6 7 8

['X', ' ', ' ', 'D', ' ', ' ', 'X', ' ', 'X'], # 0
['X', ' ', 'X', 'X', ' ', ' ', ' ', ' ', 'X'], # 1
[' ', ' ', ' ', 'D', 'X', 'X', ' ', 'X', ' '], # 2
[' ', ' ', ' ', 'D', ' ', 'X', ' ', ' ', ' '], # 3
[' ', ' ', ' ', ' ', ' ', 'X', ' ', ' ', 'X'], # 4
[' ', ' ', ' ', ' ', 'X', ' ', ' ', 'X', 'X']  # 5

]

' ' represents an open road that you can travel over in any direction (up, down, left, or right).
'X' represents an blocked road that you cannot travel through.
'D' represents a DashMart.

list of pairs [row, col]

locations = [
[200, 200],
[1, 4],
[0, 3],
[5, 8],
[1, 8],
[5, 5]
]

answer = [-1, 2, 0, -1, 6, 9]

Provided:

• city: char[][]
• locations: int[][2]

Return:

• answer: int[]
  Return a list of the distances from a given point to its closest DashMart.