Nyoj 1172 unlucky number

Nyoj 1172 unlucky number
Unlucky number time limit: 1000 MS | memory limit: 65535 KB difficulty: 0

Description

We define that only the numbers of 1 and 7 in the range [l, r] are unlucky number. For example, the numbers 1, 7, 11, and 17 are unlucky numbers, 13 and 27 are not. How many unluky numbers are there in the range [l, r ??

Input

There are multiple groups of test data (no more than 100 groups)
Enter two integers (l, r (0 = <l <= r <= 10 ^ 18) in each group)

Output

Input a result per line

Sample Input

1 7

Sample output

2

Uploaded

ACM _ Zhang Shujun

Idea: Use the preceding number as the ugly number to facilitate the subsequent number.

Create a table

Then, determine the position of l and r in the table and count unlucky numbers.

#include
      
       #include
       
        #include
        
         #includeusing namespace std;long long a[1000000];int c;void init(){    c=0;    a[c++]=1;    a[c++]=7;    int k=0;    while(a[c-1]<1e18)    {        a[c++]=a[k]*10+1;        a[c++]=a[k]*10+7;        k++;    }}int main(){    init();    long long l,r;    while(cin>>l>>r)    {        int L=0,R=0;        for(int i=0; i
         
          r)            {                R=i;                break;            }        }        if(a[L]==l||l==0) L--;        printf("%d\n",R-L-1);    }}