Leetcode 1254. Number of Closed Islands
Count the number of 4-directionally connected components of 0s in a binary grid that are completely surrounded by 1s (i.e., the component does not touch the grid boundary). This is a flood-fill/DFS-BFS style problem on an up to 100x100 grid.
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Amazon
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Late May, 2026
Staff
Mid April, 2026
Amazon
Mid-level
Given an m x n 2D binary grid 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 land.
Late January, 2026
Senior
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