简单DFS。
//#pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<cstdlib> #include<algorithm> #include<iostream> #include<sstream> #include<cmath> #include<climits> #include<string> #include<map> #include<queue> #include<vector> #include<stack> #include<set> using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair<int,int> pii; #define pb(a) push(a) #define INF 0x1f1f1f1f #define lson idx<<1,l,mid #define rson idx<<1|1,mid+1,r #define PI 3.1415926535898 template<class T> T min(const T& a,const T& b,const T& c) { return min(min(a,b),min(a,c)); } template<class T> T max(const T& a,const T& b,const T& c) { return max(max(a,b),max(a,c)); } void debug() { #ifdef ONLINE_JUDGE #else freopen("in.txt","r",stdin); //freopen("d:\out1.txt","w",stdout); #endif } int getch() { int ch; while((ch=getchar())!=EOF) { if(ch!=' '&&ch!=' ')return ch; } return EOF; } const int maxn=25; char g[maxn][maxn]; int dx[]={0,0,1,-1}; int dy[]={1,-1,0,0}; int vis[maxn][maxn]; void dfs(int x,int y,int &num) { num++; vis[x][y]=1; for(int d=0;d<4;d++) { int nx=x+dx[d]; int ny=y+dy[d]; if(g[nx][ny]=='.'&&!vis[nx][ny]) dfs(nx,ny,num); } } int main() { int n,m; while(scanf("%d%d",&m,&n)!=EOF&&n) { memset(g,'#',sizeof(g)); for(int i=1;i<=n;i++) scanf("%s",g[i]+1); int num=0; memset(vis,0,sizeof(vis)); for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) if(g[i][j]=='@') dfs(i,j,num); printf("%d ",num); } return 0; }