代码为：
#include #include #include #include #include #include #include #include #include #define eps 1e-9 #define ll long long #define INF 0x3f3f3f3f using namespace std; const int maxn=2000; double p[maxn],ans; int n,m; int main() { char str[maxn]; int temp; while(~scanf("%d%d",&n,&m)) { memset(p,0,sizeof(p)); int start=m; for(int i=1;i<=n;i++) { scanf("%s",str); p[start]=1; if(str[0]<'A'&&str[0]>='2'&&str[0]<='9') temp=str[0]-'0'; else if(str[0]=='1'||str[0]=='J'||str[0]=='Q'||str[0]=='K') temp=10; else temp=11; start+=temp; } ans=0; for(int i=start;i>=1;i--) { if(p[i]==0) { for(int j=2;j<=11;j++) { temp=(j==10?4:1); p[i]+=temp*p[i+j]; } p[i]=p[i]/13; } if(i<=10) ans+=p[i]; } printf("%.10f\n",ans/10); } return 0; }