Number of Islands

NumberOfIslands.java

public class NumberOfIslands {
    public int numIslands(char[][] grid) {
        int numOfIslands = 0;
        for (int i = 0; i < grid.length; i++) {
            char[] row = grid[i];
            for (int j = 0; j < row.length; j++) {
                if(grid[i][j] == '1') {
                    numOfIslands++;
                    scanIsland(grid, i, row, j+1);
                    scanIsland(grid, i, row, j-1);
                    scanIsland(grid, i+1, row, j);
                    scanIsland(grid, i-1, row, j);
                }
            }
        }
        return numOfIslands;
    }
    
    private void scanIsland(char[][] grid, int yIndex, char[] row, int xIndex) {
        if (yIndex >= 0 && yIndex < grid.length && xIndex >= 0 && xIndex < row.length) {
            if(grid[yIndex][xIndex] == '1') {
                grid[yIndex][xIndex] = '0';
                scanIsland(grid, yIndex, row, xIndex+1);
                scanIsland(grid, yIndex, row, xIndex-1);
                scanIsland(grid, yIndex+1, row, xIndex);
                scanIsland(grid, yIndex-1, row, xIndex);
            }
        }
    }
}

nice 👍