Codeforces 484A - Bits 二进制找1

//#pragma comment(linker, "/STACK:16777216") //for c++ Compiler
#include <stdio.h>
#include <iostream>
#include <cstring>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <algorithm>
#define ll long long
#define Max(a,b) (((a) > (b)) ? (a) : (b))
#define Min(a,b) (((a) < (b)) ? (a) : (b))
#define Abs(x) (((x) > 0) ? (x) : (-(x)))
using namespace std;

const int INF = 0x3f3f3f3f;

int Cal(long long x){
    int ret = 0;
    while (x){
        ++ret;
        x >>= 1;
    }
    return ret;
}

int main(){
    int n;
    long long l, r, ret;
    cin >> n;
    while (n--){
        cin >> l >> r;
        int lcnt = Cal(l);
        int rcnt = Cal(r);
        if (lcnt < rcnt){   //for lcnt != rcnt, answer must like 1* to r
            if (r == (1LL << rcnt) - 1){
                ret = r;
            }
            else{
                ret = (1LL << (rcnt - 1)) - 1;
            }
        }
        else{               //for lcnt == rcnt, answer must be 1* and less than r
            for (int i = 0; i < rcnt; ++i){
                if (((1LL << i) | l) <= r){
                    l |= (1LL << i);
                }
            }
            ret = l;
        }
        cout << ret << endl;
    }
    return 0;
}