2929 尋寶

#include<bits/stdc++.h>
using namespace std;

char G[25][25];
int vis[25][25];
//方向陣列，上右下左
int dx[5] = {-1,0,1,0},dy[5] = {0,1,0,-1};
int ans=0,n,m,nx,ny;
bool f = false;

void dfs(int x,int y) {
	if(G[x][y]=='*') {
		ans++;
		f=true;
		return;
	}
	for(int i=0; i<4; i++) {
		int xx = x+dx[i],yy=y+dy[i];
		if(xx>=1&&xx<=n&&yy>=1&&yy<=m
		        &&G[xx][yy]!='#'&&vis[xx][yy]==0) {
			vis[xx][yy]=1;
			dfs(xx,yy);
			vis[xx][yy]=0;
		}
	}
	return;
}

int main() {
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			cin>>G[i][j];
			if(G[i][j]=='@'){
				nx=i;
				ny=j;
			}
		}
	}
	vis[nx][ny]=1;
	dfs(nx,ny);
	if(f){
		cout<<ans;
	}else{
		cout<<-1;
	}
}