bzoj 3131: [Sdoi2013]淘金

 #include<cstdio>
 #include<iostream>
 #include<queue>
 #include<algorithm>
 #define ll long long
 #define M 40009
 #define MO 1000000007
 using namespace std;
 int a[],tot,K,anss;
 ll ans[*M],n,f[][M][],size[M],m;
 struct data
 {
     int x,y;
     ll z;
     data(int a1,int a2)
       {
         x=a1;
         y=a2;
         z=size[x]*size[y];
       }
     bool operator <(data a1)const
       {
         return z<a1.z;
       }
 };
 void dfs(int wei,ll a1,int now)
 {
     if(a1>m)
       return;
     if(wei==tot)
       {
         ans[++ans[]]=a1;
         return;
       }
     for(int i=now;i<;i++)
        dfs(wei+,a1*i,i);
     return;
 }
 bool cmp(ll a1,ll a2)
 {
     return a1>a2;
 }
 int main()
 {
     scanf("%lld%d",&n,&K);
     m=n;
     for(;n;n/=)
       a[++tot]=n%;
     dfs(,,);
     sort(ans+,ans+ans[]+);
     ans[]=unique(ans+,ans+ans[]+)-ans-;
     f[][][]=;
     for(int i=;i<tot;i++)
       {
       for(int j=;j<=ans[];j++)
         for(int k=;k<;k++)
           if(f[i][j][k])
                 for(int l=;l<;l++)
                   {
                     ll a1=ans[j]*l;
                     if(a1>ans[ans[]])
                       continue;
                     a1=lower_bound(ans+,ans+ans[]+,a1)-ans;
                     f[i+][a1][(k+l)>a[i+]]+=f[i][j][k];
                   }
     }
     for(int i=;i<ans[];i++)
       for(int j=;j<tot;j++)
         size[i]+=f[j][i][]+f[j][i][];
     for(int i=;i<=ans[];i++)
       size[i]+=f[tot][i][];
     sort(size+,size+ans[]+,cmp);
     priority_queue<data> p;
     p.push(data(,));
     for(;!p.empty();)
       {
         K--;
         data q=p.top();
         p.pop();
         anss=(anss+q.z)%MO;
         if(!K)
           break;
         if(q.x!=q.y)
           {
             anss=(anss+q.z)%MO;
             K--;
             if(!K)
                break;
             p.push(data(q.x+,q.y));
           }
         if(q.x==)
           p.push(data(q.x,q.y+));
       }
     printf("%d",anss);
     return ;
 }

DP求出转移到x坐标的数目。各位数乘积的实际数目少。