B-number

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

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

 

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数位DP

#include
      
       #include
       
        using namespace std;int a[20],pos,dp[20][3][13];int dfs(int dep,int type,int mod,bool lim){    if(!dep) return type==2 && !mod;    if(!lim && dp[dep][type][mod]!=-1) return dp[dep][type][mod];    int ans=0,up= lim ? a[dep] : 9;    for(int i=0;i<=up;i++)    {        if(type==2 || (type==1 && i==3)) ans+=dfs(dep-1,2,(mod*10+i)%13,lim && i==up);        else ans+=dfs(dep-1,i==1 ? 1 : 0,(mod*10+i)%13,lim && i==up);    }     if(!lim) dp[dep][type][mod]=ans;     return ans;}int solve(int n){    while(n) { a[++pos]=n%10; n/=10; }    return dfs(pos,0,0,1);}int main(){    int n;    memset(dp,-1,sizeof(dp));    while(scanf("%d",&n)!=EOF)    {        printf("%d\n",solve(n));        pos=0;    }}