Count Number of Islands in 2D Grid

google Given a 2D grid map of '1's (land) and '0's (water), count 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 A 2D grid map of characters '1' (land) and '0' (water). Output An integer representing the number of islands. Example Input: 11110 11010 11000 00000 Output: 1 Input: 11000 11000 00100 00011 Output: 3 Data constraints The number of rows and columns of the grid do not exceed 300. Example Input 11110 11010 11000 00000