Number of islands

class Solution { public int numIslands(char[][] grid) { //we can use depth first search for this int visited[][] = new int[grid.length][grid[0].length]; int count =0; for(int i =0;i<grid.length;i++){ for(int j =0;j<grid[0].length;j++){ if(grid[i][j] =='1' && visited[i][j] ==0){ traverse(i,j,grid,visited);//recursively visited all the connected cells count++;//increment the island count } } } return count; } public void traverse(int i, int j ,char grid[][] ,int visited[][]){ //base case if(i <0 || j<0 || i>=grid.length || j>=grid[0].length || visited[i][j] ==1 || grid[i][j]!='1') return; visited[i][j] =1;// mark the cell visited int dirs[][] = {{0,-1},{0,1},{-1,0},{1,0}}; for(int dir[] : dirs){ int in = i + dir[0]; int jn = j + dir[1]; traverse(in,jn,grid,visited); } } }