Codeforces Round #276 (Div. 2)C. Bits(构造法)

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<cmath>
#include<map>
#include<set>
#include<vector>
#include<algorithm>
#include<stack>
#include<queue>
#include<cctype>
#include<sstream>
using namespace std;
#define pii pair<int,int>
#define LL long long int
const int eps=1e-8;
const int INF=1000000000;
const int maxn=10000+5;
int n;
LL l,r,p;

int main()
{
    //freopen("in9.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    scanf("%d",&n);
    while(n--)
    {
        scanf("%I64d%I64d",&l,&r);
        p=1;
        while(1)
        {
            if((l|p)>r)
            {
                printf("%I64d\n",l);
                break;
            }
            else
            {
                l|=p;
                p*=2;
            }
        }
    }
    //fclose(stdin);
    //fclose(stdout);
    return 0;
}