HDU 3652B-number 数位dp

G - B-number

Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u

Submit Status Practice HDU 3652

Appoint description: System Crawler  (2016-04-22)

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

131002001000 

 

Sample Output

1122 

 数位dp flag表示状态 mod判断是否能整除

ACcode：

#include <iostream>#include <cstdio>#include <cstring>#define ll long longusing namespace std;int dp[25][25][3];int date[25];int dfs(int pos,int mod,int flag,bool limit){    if(!pos)return mod==0&&flag==2;    if(!limit&&dp[pos][mod][flag]!=-1)return dp[pos][mod][flag];    int ret=0;    int ed=limit?date[pos]:9;    for(int i=0;i<=ed;i++){        int tmp=flag;        int modd=(mod*10+i)%13;        if(flag==1&&i==3)            tmp=2;        else if(flag==0&&i==1)            tmp=1;        else if(flag==1&&i!=1&&i!=3)            tmp=0;        ret+=dfs(pos-1,modd,tmp,limit&&i==ed);    }    return limit?ret:dp[pos][mod][flag]=ret;}void doit(int n){    int len=0;    while(n){        date[++len]=n%10;        n/=10;    }    printf("%d\n",dfs(len,0,0,1));}int main(){    int n;memset(dp,-1,sizeof(dp));    while(~scanf("%d",&n))doit(n);}