WA了7个点求助（玄关）

#include <bits/stdc++.h>
using namespace std;
int n,m,ex,ey;
char a[505][505]; 
bool book[505][505];
void dfs(int x,int y)
{
	if(x>n||y>m||x<1||y<1)
	{
		return;
	}
	book[x][y]=1;
	if(book[x+1][y]==0&&a[x+1][y]!='#')
	{
		dfs(x+1,y);
	}
	if(book[x-1][y]==0&&a[x-1][y]!='#')
	{
		dfs(x-1,y);
	}
	if(book[x][y+1]==0&&a[x][y+1]!='#')
	{
		dfs(x,y+1);
	}
	if(book[x][y-1]==0&&a[x][y-1]!='#')
	{
		dfs(x,y-1);
	}
}
signed main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=m;j++)
		{
			cin>>a[i][j];
			if(a[i][j]=='g')
			{
				ex=i;
				ey=j;
			}
		}
	}
	dfs(1,1);
	if(book[ex][ey])
	{
		cout<<"Yes";
	}else
	{
		cout<<"No";
	}
	return 0;
}