Deep Blue Sea EXAM06

#include<stdio.h>
#include<queue>
using namespace std;
char sea[510][510];
bool visited[510][510];
int n,m;
typedef struct{
    int I;
    int J;
}pos;
int max(int a,int b){
    return (a > b ? a : b);
}

int dfs(int I,int J){
pos move[4] = {{-1,0},{0,1},{1,0},{0,-1}};
    queue<pos> q;
    q.push({I,J});
    int count = 0;
    while(!q.empty()){
        int nowI = q.front().I;
        int nowJ = q.front().J;
        q.pop();
        if(!visited[nowI][nowJ]){
            visited[nowI][nowJ] = true;
            if(sea[nowI][nowJ] == '*'){
                count++;
            }
            for(int i=0;i<4;i++){
                int newI = nowI + move[i].I;
                int newJ = nowJ + move[i].J;
                if(newI < 0)newI = n-1;
                else if(newI >= n)newI = 0;
                if(newJ < 0)newJ = m-1;
                else if(newJ >= m)newJ = 0;

                if(sea[newI][newJ] != '#' && !visited[newI][newJ]){
                    q.push({newI,newJ});
                }
            }
        }
    }
    return count;
}

int main()
{
    scanf("%d %d",&n,&m);
    for(int i=0;i<n;i++){
        scanf("%s",sea[i]);
    }
    int maxa = 0;
    for(int i=0;i<n;i++){
        for(int j=0;j<m;j++){
            if(sea[i][j] != '#'){
                int cal = dfs(i,j);
                maxa = max(maxa,cal);
            }
        }
    }
    printf("%d",maxa);
}