Magic Number(打表）

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3622

#include<iostream>
using namespace std ;
long long f[55] = {1,2,5,10,20,25,50,100,125,200,250,500,1000,1250,2000,2500,
5000,10000,12500,20000,25000,50000,100000,125000,200000,250000,500000,1000000,
1250000,2000000,2500000,5000000,10000000,12500000,20000000, 25000000, 50000000,
100000000 ,125000000, 200000000, 250000000, 500000000,1000000000 ,1250000000,
 2000000000, 2500000000,5000000000,10000000000 ,12500000000, 20000000000};
int main()
{
    long long m, n ;
    while(cin>>m>>n)
    {
        long long num = 0 ;
        for(long long i=0; i<55; i++)
        {
            if(f[i]>=m&&f[i]<=n)
            num++ ;
            if(f[i]>n)
            break ;
        }
        cout<<num<<endl ;
    }
    return 0 ;
}