Number of Islands: 2D Grid BFS/DFS Traversal

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 water. ### Input Format - First line contains two integers `m` and `n` representing the row and column dimensions. - The next `m` lines each contain `n` space-separated binary characters (`1` or `0`). ### Output Format - Print a single integer representing the number of islands. ### Constraints - `m == grid.length` - `n == grid[i].length` - `1 <= m, n <= 300` - `grid[i][j]` is `'0'` or `'1'`