B-number

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 6444 Accepted Submission(s):
3739

Problem Description

A wqb-number, or B-number for short, is a non-negative
integer whose decimal form contains the sub- string "13" and can be divided by
13. For example, 130 and 2613 are wqb-numbers, but 143 and 2639 are not. Your
task is to calculate how many wqb-numbers from 1 to n for a given integer
n.

Input

Process till EOF. In each line, there is one positive
integer n(1 <= n <= 1000000000).

Output

Print each answer in a single line.

Sample Input

13
100
200
1000

Sample Output

1
1
2
2

Author

wqb0039

Source

2010
Asia Regional Chengdu Site —— Online Contest

题意：找出1~n范围内含有13并且能被13整除的数字的个数

思路:http://blog.csdn.net/libin56842/article/details/10026063

#include<cstdio>

#include<iostream>

#include<cstring>

using namespace std;

int dit[],f[][][];

int dfs(int pos,int mod,int have,int lim)

{

    int num,ans,mod_x,have_x;

    if(pos<=) return mod== && have==;

    if(!lim && f[pos][mod][have]!=-) return f[pos][mod][have];

    num=lim?dit[pos]:;ans=;

    for(int i=;i<=num;i++)

    {

        mod_x=(mod*+i)%; have_x=have;

        if(have== && i==) have_x=;

        if(have== && i!=) have_x=;

        if(have== && i==) have_x=;

        ans+=dfs(pos-,mod_x,have_x,lim&&i==num);

    }

    if(!lim) f[pos][mod][have]=ans;

    return ans;

}

int main()

{

    int n,len;

    while(~scanf("%d",&n))

    {

        memset(dit,,sizeof dit);

        memset(f,-,sizeof f);len=;

        while(n)

        {

            dit[++len]=n%;

            n/=;

        }dit[len+]=;

        printf("%d\n",dfs(len,,,));

    }

    return ;

}

巴特西

hdu3652B-number（数位dp）

B-number

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