#2257

Count Unguarded Cells in the Grid

pupil · 580 · lc medium +29 · verified · 69% accepted · 1,291 likes · top 76%

Description

You are given two integers m and n representing a 0-indexed m x n grid. You are also given 2D integer arrays guards and walls where guards[i] = [rowi, coli] and walls[j] = [rowj, colj] give the grid positions of guards and walls.

Each guard can see in all four cardinal directions until blocked by a wall or another guard. A cell is guarded if at least one guard can see it.

Return the number of empty cells that are not guarded.

Example 1:

Input: m = 4, n = 6, guards = [[0,0],[1,1],[2,3]], walls = [[0,1],[2,2],[1,4]]

Output: 7

Explanation: The guarded and unguarded cells are shown in red and green respectively in the above diagram.

There are a total of 7 unguarded cells, so we return 7.

Example 2:

Input: m = 3, n = 3, guards = [[1,1]], walls = [[0,1],[1,0],[2,1],[1,2]]

Output: 4

Explanation: The unguarded cells are shown in green in the above diagram.

There are a total of 4 unguarded cells, so we return 4.

Code

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class Solution:
    def countUnguarded(self, m: int, n: int, guards: List[List[int]], walls: List[List[int]]) -> int:

class Solution:
    def countUnguarded(self, m: int, n: int, guards: List[List[int]], walls: List[List[int]]) -> int: