J - 吉哥系列故事――恨7不成妻

 #include "cstdio"
 #include "math.h"
 #include "cstring"
 #define mod 1000000007LL
 #define LL long long

 struct node
 {
     LL cnt,sum,sqsum;
     node() {cnt=-;sum=sqsum=;}
     node(LL cnt,LL sum,LL sqsum):cnt(cnt),sum(sum),sqsum(sqsum) {}
 }dp[][][];

 LL a[],p[];

 node dfs(int pos,int re1,int re2,bool limit)
 {
     if(!pos) return re1!=&&re2!=?node(,,):node(,,);
     if(!limit&&dp[pos][re1][re2].cnt!=-) return dp[pos][re1][re2];
     int up=limit?a[pos]:;
     node ans;ans.cnt = ;
     for(int i=;i<=up;i++)
     {
         if(i==) continue;
         node next=dfs(pos-,(re1+i)%,(re2*+i)%,limit&&i==up);
         ans.cnt+=next.cnt;
         ans.cnt%=mod;
         ans.sum+=(next.sum+((p[pos]*i)%mod)*next.cnt%mod)%mod;
         ans.sum%=mod;
         ans.sqsum+=(next.sqsum+((*p[pos]*i)%mod)*next.sum)%mod;
         ans.sqsum%=mod;
         ans.sqsum+=((next.cnt*p[pos])%mod*p[pos]%mod*i*i%mod);
         ans.sqsum%=mod;
     }
     if(!limit) dp[pos][re1][re2]=ans;
     return ans;
 }

 LL f(LL x)
 {
     int pos=;
     while(x)
     {
         a[++pos]=x%;
         x/=;
     }
     node tt=dfs(pos,,,true);
     return tt.sqsum;
 }

 int main()
 {
     int T;
     LL l,r;
     scanf("%d",&T);
     p[]=;
     for(int i=;i<=;i++) p[i]=(p[i-]*)%mod;
     while(T--)
     {
         scanf("%I64d%I64d",&l,&r);
         LL ans=f(r);
         ans-=f(l-);
         printf("%I64d\n",(ans%mod+mod)%mod);
     }
 }