feat: 0100.岛屿最大面积 Java实现

problems/kamacoder/0100.岛屿的最大面积.md

@@ -224,6 +224,127 @@ public:
 
 ### Java
 
+```java
+import java.util.*;
+import java.math.*;
+
+/**
+ * DFS版
+ */
+public class Main{
+
+    static final int[][] dir={{0,1},{1,0},{0,-1},{-1,0}};
+    static int result=0;
+    static int count=0;
+
+    public static void main(String[] args){
+        Scanner scanner = new Scanner(System.in);
+        int n = scanner.nextInt();
+        int m = scanner.nextInt();
+        int[][] map = new int[n][m];
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                map[i][j]=scanner.nextInt();
+            }
+        }
+        boolean[][] visited = new boolean[n][m];
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                if(!visited[i][j]&&map[i][j]==1){
+                    count=0;
+                    dfs(map,visited,i,j);
+                    result= Math.max(count, result);
+                }
+            }
+        }
+        System.out.println(result);
+    }
+
+    static void dfs(int[][] map,boolean[][] visited,int x,int y){
+                count++;
+                visited[x][y]=true;
+                for (int i = 0; i < 4; i++) {
+                    int nextX=x+dir[i][0];
+                    int nextY=y+dir[i][1];
+                    //水或者已经访问过的跳过
+                    if(nextX<0||nextY<0
+                    ||nextX>=map.length||nextY>=map[0].length
+                    ||visited[nextX][nextY]||map[nextX][nextY]==0)continue;
+                    
+                    dfs(map,visited,nextX,nextY);
+                }
+            }
+}
+```
+
+```java
+import java.util.*;
+import java.math.*;
+
+/**
+ * BFS版
+ */
+public class Main {
+    static class Node {
+        int x;
+        int y;
+
+        public Node(int x, int y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    static final int[][] dir = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
+    static int result = 0;
+    static int count = 0;
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        int n = scanner.nextInt();
+        int m = scanner.nextInt();
+        int[][] map = new int[n][m];
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                map[i][j] = scanner.nextInt();
+            }
+        }
+        boolean[][] visited = new boolean[n][m];
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                if (!visited[i][j] && map[i][j] == 1) {
+                    count = 0;
+                    bfs(map, visited, i, j);
+                    result = Math.max(count, result);
+                }
+            }
+        }
+        System.out.println(result);
+    }
+
+    static void bfs(int[][] map, boolean[][] visited, int x, int y) {
+        Queue<Node> q = new LinkedList<>();
+        q.add(new Node(x, y));
+        visited[x][y] = true;
+        count++;
+        while (!q.isEmpty()) {
+            Node node = q.remove();
+            for (int i = 0; i < 4; i++) {
+                int nextX = node.x + dir[i][0];
+                int nextY = node.y + dir[i][1];
+                if (nextX < 0 || nextY < 0 || nextX >= map.length || nextY >= map[0].length || visited[nextX][nextY] || map[nextX][nextY] == 0)
+                    continue;
+                q.add(new Node(nextX, nextY));
+                visited[nextX][nextY] = true;
+                count++;
+            }
+        }
+    }
+}
+
+```
+
+
 ### Python
 
 DFS