HDOJ 3652 BBnumber

题目意思   1到N 不包含 13 作为字串并且 是13的倍数

#include<iostream>
#include<stdio.h>
#include<cstring>
#include<algorithm>
using namespace std;

long long N,arr[32],dp[32][3][13];
long long DFS( int pos,int flag,int t,int limit )
{
    if( pos == -1 )
    {
        if( flag == 2 && t == 0 )return 1;
        return 0;
    }
    if( !limit && dp[pos][flag][t] != -1 ) return dp[pos][flag][t];
    int end = limit?arr[pos]:9;long long ans = 0;
    for( int i = 0; i <= end; i++ )
    {
        int tab = flag;
        if( tab == 0 && i == 1 )tab = 1;
        if( tab == 1 && i == 3 )tab = 2;
        if( tab == 1 && i == 1 )tab = 1;
        if( tab == 1 && i != 1 && i != 3 )tab = 0;
        int num = (t*10+i)%13;
        ans += DFS( pos-1,tab,num,limit&&(i==arr[pos]) );
    }
    if( !limit )dp[pos][flag][t] = ans;
    return ans;
}
long long work( long long num )
{
    int k = 0;
    while( num )
    {
        arr[k++] = num%10;
        num /= 10;
    }
    memset( dp,-1,sizeof(dp) );
    return DFS( k-1,0,0,1 );
}
int main( )
{
   //freopen("in.txt","r",stdin);
   //freopen("out.txt","w",stdout);
   while( scanf("%I64d",&N) != EOF )
   printf("%I64d\n",work(N));
   return 0;
}