二进制 模拟 codeforces 485C

/*************************************************************************
> File Name: 485C.cpp
> Author: flyasdfvcxz
> Mail: 1099431883@qq.com
> Created Time: Fri 07 Nov 2014 05:06:52 PM CST
************************************************************************/

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <vector>
#include <queue>
#include <map>
#include <ctime>
#include <cmath>
#define ll long long
using namespace std;
int n;
ll l, r;
int main()
{
cin >> n;
while (n--)
{
cin >> l >> r;
if (l == r)
{
cout << l << endl;
continue;
}
ll res = 0;
while (1)
{
int pos = -1;
ll ans = -1;
for (int i = 1; ; ++i)
{
ll cur = (1LL << i) - 1;
if (cur < l)
{
pos = i;
}
else if (cur >= l && cur <= r)
{
ans = cur;
}
else if (cur > r)
{
break;
}
}
if (ans != -1)
{
res |= ans;
cout << res << endl;
break;
}
else
{
ll tmp = (1LL << pos);
res |= tmp;
l -= tmp;
r -= tmp;
}
}
}
return 0;
}