Number of Islands with Large Map Follow-up

Problem: Number of Islands, with Large Map Follow-up Given a 2D grid grid consisting of '1' and '0', where: '1' represents land; '0' represents water. An island is formed by horizontally or vertically adjacent land cells. You may assume that the grid is surrounded by water. Return the number of islands in the grid. Follow-up What if the map is too large to fit into memory? Describe a scalable design, for example: Split the map into blocks/chunks; Count connected components inside each block; Merge land components touching across neighboring block boundaries; Use Union Find / Disjoint Set Union to maintain island merges across blocks. Input Format m n row_0 row_1 ... row_{m-1} Each row may be a continuous string like 11000, or space-separated values like 1 1 0 0 0. Output Format Print one integer, the number of islands. Constraints Base problem: 1 <= m, n <= 300 grid[i][j] in {'0', '1'} Follow-up scenario: The map is much larger than memory; Only chunks or streams of the input can be loaded at once. Example Input: 4 5 11110 11010 11000 00000 Output: 1 Example Input 4 5 11110 11010 11000 00000 Output 1