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core18 min

Number of Islands

Number of Islands

Given an m x n 2D binary grid which represents a map of '1's (land) and '0's (water), return the number of islands.

An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

const grid = [
  ["1", "1", "1", "1", "0"],
  ["1", "1", "0", "1", "0"],
  ["1", "1", "0", "0", "0"],

Run your code to see results.

Stuck? This challenge exercises:

javascript.data-structures
["0", "0", "0", "0", "0"]
];
numIslands(grid); // 1