How to Solve Grid Illumination Problem
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Grid Illumination
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 th...
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Understanding the Grid Illumination Problem
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Problem Statement
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.
Grid Illumination
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Examples
n = 5, lamps = [[0,0],[4,4]], queries = [[1,1],[1,0]][1,0]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.
n = 5, lamps = [[0,0],[4,4]], queries = [[1,1],[1,1]][1,1]n = 5, lamps = [[0,0],[0,4]], queries = [[0,4],[0,1],[1,4]][1,1,0]Constraints
1 <= n <= 1090 <= lamps.length <= 200000 <= queries.length <= 20000lamps[i].length == 20 <= rowi, coli < nqueries[j].length == 20 <= rowj, colj < nHow Interview Coder Helps with Leetcode Problems
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