[cf908G]New Year and Original Order

Defined state f [i] [j] [k] [x] indicates the number of digits t i j have bits is greater than x, k bit is equal to x, but unacceptable complexity, may be found to change the state of F [i] [ j] [x] has a front j i is greater than the number of digits equal to x programs, can be quickly transferred

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define mod 1000000007
 4 int n,ans,f[1005][1005][11][2];
 5 char s[1005];
 6 int main(){
 7     scanf("%s",s);
 8     n=strlen(s);
 9     for(int i=0;i<10;i++)f[0][0][i][0]=1;
10     for(int i=0;i<n;i++){
11         int p=(s[i]-'0'); 
12         for(int j=0;j<=i;j++)
13             for(int k=0;k<10;k++)
14                 for(int l=0;l<2;l++)
15                     for(int t=0;t<=max(p,9*l);t++){
16                         f[i+1][j+(k<=t)][k][l|(t<p)]+=f[i][j][k][l];
17                         f[i+1][j+(k<=t)][k][l|(t<p)]%=mod;
18                     }
19     }
20     for(int i=1,s=0;i<=n;i++){
21         s=(10LL*s+1)%mod;
22         for(int j=1;j<10;j++)
23             for(int k=0;k<2;k++)ans=(ans+1LL*s*f[n][i][j][k])%mod; 
24     }
25     printf("%d",ans); 
26 }

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