mediumBlind 75
Number of Islands
Given a 2D grid of '1's (land) and '0's (water) Count the number of islands An island is formed by connecting adjacent lands horizontally/vertically Example: [["1","1","0"],["1","1","0"],["0","0","1"]] => 2
Each unvisited land cell starts one flood fill. I count the fills, not the cells — that reframing is the whole solution.
Arrays & HashingGraphsBFS / DFS
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1Count Number of Islandsmedium
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Based onLeetCode