LeetCode-Number of Islands

 1 public class Solution {
 2     int[][] moves = new int[][]{{1,0},{-1,0},{0,1},{0,-1}};
 3     
 4     public int numIslands(char[][] grid) {
 5         if (grid.length==0 || grid[0].length==0) return 0;
 6         int count = 0;
 7 
 8         for (int i=0;i<grid.length;i++)
 9             for (int j=0;j<grid[0].length;j++)
10                 if (grid[i][j] == ‘1‘){
11                     count++;
12                     markOneIsland(grid,new int[]{i,j});
13                 }
14 
15         return count;
16     }
17     
18     public void markOneIsland(char[][] grid, int[] start){
19         Deque<int[]> pointList = new LinkedList<int[]>();
20         pointList.add(start);        
21 
22         while (!pointList.isEmpty()){
23             int[] head = pointList.poll();
24             for (int i=0;i<4;i++){
25                 int[] next = new int[]{head[0]+moves[i][0],head[1]+moves[i][1]};            
26                 if (next[0]>=0 && next[0]<grid.length && next[1]>=0 && next[1]<grid[0].length && grid[next[0]][next[1]] == ‘1‘){
27                     pointList.add(next);
28                     grid[next[0]][next[1]] = ‘2‘;
29                 }
30             }
31         }
32     }
33 }