洛谷 P2431 正妹吃月饼

P2431 正妹吃月饼

求l到r之间有多少个二进制1

#include<iostream>
#include<cstdio>
#include<cstring>
#define LL long long
using namespace std;
LL ans;
char ch;
inline void read(LL &now)
{
    int f=1; ch=getchar(); now=0;
    while(ch>'9'||ch<'0') {if(ch=='-') f*=-1; ch=getchar();}
    while(ch>='0'&&ch<='9') now=now*10+ch-'0',ch=getchar();
    now*=f;
}

int main()
{
    LL l,r;
    read(l); read(r);
    while((l|(l+1))<=r) l|=l+1;
    while(l)
    {
        ans+=l&1;
        l>>=1;
    }
    cout<<ans<<endl;
    return 0;
}