hdoj3652 B-number

题意：给出n，问1-n中有13且能整除13的数数量。

就是hd3555和codeforces beautiful number的合成版。dp记录待填长度，是否带有13，前面数的模13余数，前一个数是k的时候的b-number数数量。

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cstring>
#include <map>
#include <queue>
#include <set>
#include <cassert>
using namespace std;
const double EPS=1e-;
const int SZ=,INF=0x7FFFFFFF;
typedef long long lon;
int dp[][][][];

int dfs(int pos,int sum,int pre,int limit,string &str,int inc)
{
    if(pos==str.size())return inc&&(sum%==);
    if(!limit&&dp[str.size()-pos-][sum][pre][inc]!=-)return dp[str.size()-pos-][sum][pre][inc];
    int up=limit?str[pos]-'':;
    int res=;
    for(int i=;i<=up;++i)
    {
        int nexsum=(sum*+i)%;
        if(pre==&&i==)res+=dfs(pos+,nexsum,i,limit&&i==str[pos]-'',str,);
        else res+=dfs(pos+,nexsum,i,limit&&i==str[pos]-'',str,inc);
        //if(pos==1&&pre==1)cout<<i<<" "<<res<<" "<<endl;
    }
    if(!limit)dp[str.size()-pos-][sum][pre][inc]=res;
    return res;
}

int work(string &str)
{
    return dfs(,,,,str,);
}

int main()
{
    std::ios::sync_with_stdio();
    //freopen("d:\\1.txt","r",stdin);
    //lon casenum;
    //cin>>casenum;
    memset(dp,-,sizeof(dp));
    //for(lon time=1;time<=casenum;++time)
    string str;
    for(lon time=;cin>>str;++time)
    {
        cout<<work(str)<<endl;
    }
    return ;
}