HDU 3652 B-number（数位DP）

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <vector>
#include <string>
#include <cctype>
#include <complex>
#include <cassert>
#include <utility>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;
typedef pair<int,int> PII;
typedef long long ll;
#define lson l,m,rt<<1
#define pi acos(-1.0)
#define rson m+1,r,rt<<11
#define All 1,N,1
#define read freopen("in.txt", "r", stdin)
const ll  INFll = 0x3f3f3f3f3f3f3f3fLL;
const int INF= 0x7ffffff;
const int mod =  1000000007;
ll dp[15][2][2][13],n;
int bit[15];
ll dfs(int i,int j,int f,int mod,int e){
    if(i==0)return f&&(mod%13==0)?1:0;
    if(!e&&dp[i][j][f][mod]!=-1)return dp[i][j][f][mod];
    int u=e?bit[i]:9;
    ll num=0;
    for(int v=0;v<=u;++v)
    {
        int tm=(mod*10+v)%13;
        if(f)num+=dfs(i-1,v==1,1,tm,e&&(v==u));
        else num+=dfs(i-1,v==1,j&&v==3,tm,e&&(v==u));
    }
    return e?num:dp[i][j][f][mod]=num;
}
ll solve(ll x){
    int len=0;
    while(x){
        bit[++len]=x%10;
        x/=10;
    }
    return dfs(len,0,0,0,1);
}
int main()
{
    memset(dp,-1,sizeof(dp));
    while(~scanf("%I64d",&n)){
        printf("%I64d\n",solve(n));
    }
return 0;
}