Merge pull request #1637 from YunChenCloud/master

添加0200.岛屿数量.广搜版 Java版本

problems/0200.岛屿数量.广搜版.md

@@ -144,3 +144,50 @@ public:
 };
 
 ```
+
+## 其他语言版本
+
+### Java
+
+```java
+class Solution {
+
+    boolean[][] visited;
+    int[][] move = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
+
+    public int numIslands(char[][] grid) {
+        int res = 0;
+        visited = new boolean[grid.length][grid[0].length];
+        for(int i = 0; i < grid.length; i++) {
+            for(int j = 0; j < grid[0].length; j++) {
+                if(!visited[i][j] && grid[i][j] == '1') {
+                    bfs(grid, i, j);
+                    res++;
+                }
+            }
+        }
+        return res;
+    }
+
+    //将这片岛屿上的所有陆地都访问到
+    public void bfs(char[][] grid, int y, int x) {
+        Deque<int[]> queue = new ArrayDeque<>();
+        queue.offer(new int[]{y, x});
+        visited[y][x] = true;
+        while(!queue.isEmpty()) {
+            int[] cur = queue.poll();
+            int m = cur[0];
+            int n = cur[1];
+            for(int i = 0; i < 4; i++) {
+                int nexty = m + move[i][0];
+                int nextx = n + move[i][1];
+                if(nextx < 0 || nexty == grid.length || nexty < 0 || nextx == grid[0].length) continue;
+                if(!visited[nexty][nextx] && grid[nexty][nextx] == '1') {
+                    queue.offer(new int[]{nexty, nextx}); 
+                    visited[nexty][nextx] = true; //只要加入队列就标记为访问
+                }
+            }
+        }
+    }
+}
+```