http://codeforces.com/problemset/problem/768/B B. Code For 1

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 long long bit[70];
 4 void init()
 5 {
 6     bit[1]=1;
 7     for(int i=2;i<=55;++i)
 8     {
 9         bit[i]=2*bit[i-1]+1;
10     }
11 }
12 long long getRes(long long n,long long  x)
13 {//数字n,第x位
14     if(x==0)return 0;
15     long long res=0;
16     long long bitsCnt=bit[lower_bound(bit+1,bit+55+1,n/2)-bit];
17     //printf("n=%I64d,x=%I64d,bitsCnt=%I64d\n",n,x,bitsCnt);
18     if(n==1)return 1;
19     if(x==bitsCnt+1)
20     {
21         if(n%2==1)res++;
22         res+=n/2;
23         return res;
24     }
25     else if(x>bitsCnt+1)
26     {
27         if(n%2==1)res++;
28         res+=n/2;
29         res+=getRes(n/2,x-bitsCnt-1);
30     }
31     else 
32     {
33         res+=getRes(n/2,x);
34     }
35     //printf("res=%I64d\n",res);
36     return res;
37 }
38 int main() {
39     long long n,l,r;
40     init();
41     scanf("%I64d%I64d%I64d",&n,&l,&r);
42     if(n==0)
43     {
44         printf("0\n");
45         return 0;
46     }
47     int index=lower_bound(bit+1,bit+55+1,n)-bit;
48     long long res1=getRes(n,l-1);
49     long long res2=getRes(n,r);
50     //printf("res1=%I64d,res2=%I64d\n",res1,res2);
51     printf("%I64d\n",res2-res1);
52     return 0;
53 }