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