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Count connected land components in a grid

LinkedInSoftware Engineer · Onsite
MediumSoftware EngineerOnsiteCoding & Algorithms

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This question evaluates understanding of grid traversal and graph connectivity concepts, focusing on modeling a 2D matrix as adjacency relationships within the coding and algorithms domain.

You are given a 2D grid of characters where:

  • '1' represents land
  • '0' represents water

A group of land cells forms an island if they are connected 4-directionally (up, down, left, right). Determine the number of islands in the grid.

Input

  • grid: an m x n matrix of characters ('0' or '1').

Output

  • Return an integer: the number of islands.

Constraints

  • 1 <= m, n <= 300
  • grid[i][j] ∈ {'0','1'}

Notes

  • Diagonal adjacency does not connect islands.
  • You may modify the grid in-place if desired.