细心注意输入的格式

#include <bits/stdc++.h>
using namespace std;
const int N = 1001;
int n,vis[N][N],m;
char a[N][N];
int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};
int flag=0,sx,sy,cnt;
void dfs(inlinet x,int y)
{

	for(int i=0;i<4;++i)
	{
		int nx = dx[i]+x;
		int ny = dy[i]+y;
		if(nx>=1 and ny>=1 and nx<=m and ny<=n and !vis[nx][ny] and a[nx][ny]!='#')
		{	cnt++;
			vis[nx][ny]=1;
			dfs(nx,ny);
		}
	}
	return;
	
}
int main()
{
	cin>>n>>m;
	for(int i=1;i<=m;++i)
	{
		for(int j=1;j<=n;++j)	
		{
			cin>>a[i][j];
			if(a[i][j]=='@')
			{
				sx=i;
				sy=j;
			}
		}
	}
	
	dfs(sx,sy);
	cout<<cnt;
		
	return 0;
}