mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
74 lines
1.9 KiB
C++
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);
|
|
}
|
|
}
|