- Difficulty: Hard
- Tags: LeetCode, Hard, Array, Hash Table, leetcode-1001, O(l + q), O(l)
Problem
There is a 2D grid
of size n x n
where each cell of this grid has a lamp that is initially turned off.
You are given a 2D array of lamp positions lamps
, where lamps[i] = [rowi, coli]
indicates that the lamp at grid[rowi][coli]
is turned on. Even if the same lamp is listed more than once, it is turned on.
When a lamp is turned on, it illuminates its cell and all other cells in the same row, column, or diagonal.
You are also given another 2D array queries
, where queries[j] = [rowj, colj]
. For the jth
query, determine whether grid[rowj][colj]
is illuminated or not. After answering the jth
query, turn off the lamp at grid[rowj][colj]
and its 8 adjacent lamps if they exist. A lamp is adjacent if its cell shares either a side or corner with grid[rowj][colj]
.
Return an array of integers ans
, where ans[j]
should be 1
if the cell in the jth
query was illuminated, or 0
if the lamp was not.
Example 1:
Input: n = 5, lamps = [[0,0],[4,4]], queries = [[1,1],[1,0]] Output: [1,0] Explanation: We have the initial grid with all lamps turned off. In the above picture we see the grid after turning on the lamp at grid[0][0] then turning on the lamp at grid[4][4]. The 0th query asks if the lamp at grid[1][1] is illuminated or not (the blue square). It is illuminated, so set ans[0] = 1. Then, we turn off all lamps in the red square. The 1st query asks if the lamp at grid[1][0] is illuminated or not (the blue square). It is not illuminated, so set ans[1] = 0. Then, we turn off all lamps in the red rectangle.
Example 2:
Input: n = 5, lamps = [[0,0],[4,4]], queries = [[1,1],[1,1]] Output: [1,1]
Example 3:
Input: n = 5, lamps = [[0,0],[0,4]], queries = [[0,4],[0,1],[1,4]] Output: [1,1,0]
Constraints:
1 <= n <= 109
0 <= lamps.length <= 20000
0 <= queries.length <= 20000
lamps[i].length == 2
0 <= rowi, coli < n
queries[j].length == 2
0 <= rowj, colj < n