OJ-Problems-Source/HDOJ/3326_autoAC.cpp
2016-09-01 20:54:35 +08:00

74 lines
1.9 KiB
C++

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
int n,m[5],l[5],len;
double p[5],dp[6][3125][32];
bool f[6][3125][32];
char ans[100];
double solve(int g,int r,int mask)
{
if(mask==0) return 1.0;
if(f[g][r][mask]) return dp[g][r][mask];
int a[5],c=r;
double b[2][5],t1,t2;
for(int i=n-1;i>=0;--i)
{
a[i]=c%5;
c/=5;
}
for(int i=0;i<n;++i)
{
if(l[i]) t1=p[i]/l[i]*(l[i]-a[i]);
else t1=0.0;
t2=(1-p[i])/(m[i]-l[i])*(m[i]-l[i]-g+a[i]);
if(t1+t2<1e-8) b[0][i]=b[1][i]=0.0;
else
{
b[0][i]=(1-p[i])/(m[i]-l[i])/(t1+t2);
b[1][i]=p[i]/l[i]/(t1+t2);
}
}
dp[g][r][mask]=0.0;
for(int i=mask;;i=((i-1)&mask))
{
double tmp=0.0;
int choose[5],chs=0;
for(int j=0;j<n;++j)
{
if(i&(1<<j)) choose[j]=1;
else choose[j]=0;
if((mask&(1<<j))&&choose[j]+a[j]>l[j]) goto fuck;
if((mask&(1<<j))&&choose[j]==0&&m[j]-l[j]-g+a[j]<=0) goto fuck;
chs=chs*5+choose[j]+a[j];
}
for(int j=mask;j;j=((j-1)&mask))
{
double pp=1.0;
for(int k=0;k<n;++k)
if(j&(1<<k)) pp*=b[choose[k]][k];
else if(mask&(1<<k)) pp*=1-b[choose[k]][k];
tmp+=pp*solve(g+1,chs,mask-j);
}
dp[g][r][mask]=max(dp[g][r][mask],tmp);
fuck:if(i==0) break;
}
f[g][r][mask]=1;
return dp[g][r][mask];
}
int main()
{
while(scanf("%d",&n)&&n)
{
for(int i=0;i<n;++i) scanf("%d%d%lf",m+i,l+i,p+i);
memset(f,0,sizeof(f));
memset(ans,0,sizeof(ans));
sprintf(ans,"%.3lf",solve(0,0,(1<<n)-1));
len=strlen(ans);
while(ans[len-1]=='0')
ans[--len]='\0';
if(ans[len-1]=='.') ans[len-1]='\0';
printf("%s\n",ans);
}
}