static int r=0, c=0;

static int[][] d = {{1,0}, {-1,0}, {0,1}, {0,-1}};

static class Point {

public int x, y;

public Point(int x, int y) {

this.x = x;

this.y = y;

}

}

public int solution(int[][] maps){

int answer = 0;

r = maps.length;

c = maps[0].length;

boolean visited[][] = new boolean[r][c];

int adj[] = new int[2500];

int num = 1;

for(int i=0; i<r; i++) {

for(int j=0; j<c; j++) {

if(maps[i][j]==1 && !visited[i][j]) {

num++;

Queue<Point> q = new LinkedList<Point>();

q.add(new Point(i, j));

visited[i][j] = true;

maps[i][j] = num;

while(!q.isEmpty()) {

Point p = q.poll();

for(int k=0; k<4; k++) {

Point np = new Point(p.x+d[k][0], p.y+d[k][1]);

if(!inRange(np)) adj[num]++;

else if(maps[np.x][np.y]==1) {

visited[np.x][np.y] = true;

maps[np.x][np.y] = num;

q.add(np);

} else if(maps[np.x][np.y]==0) {

adj[num]++;

}

}

}

answer = Math.max(answer, adj[num]);

}

}

}

return answer;

}

public boolean inRange(Point p) {

return p.x>=0 && p.y>=0 && p.x<r && p.y<c;

}