484A - Bits - CodeForces Solution

#include <iostream>
#include <cmath>
#include <vector>
#include <string>
#include <algorithm>
#include <cstring>
#include <unordered_map>
#include <queue>
#include <deque>
#include <unordered_set>
#include <stack>
#include <set>
#include <utility>
#include <iomanip>
#include <climits>
#include <map>
#include<limits>
#include <cfloat>
#include<numeric>
#define vi vector<int>
#define vii vector<vi>
#define REP(i,a,b) for(int i=a; i<b; i++)
#define REPeq(i,a,b) for(int i=a; i<=b; i++)
#define ll long long int 
using namespace std;

void file_in_out()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif
}




ll query(ll l, ll r)
{
    if(l==r) return l;

    ll num = 1;
    while(num*2<=r)
    {
        num*=2;
    }

    if(num<=l)
    {
        return query(l-num,r-num)+num;
    }
    else if(num*2 - 1<=r)
    {
        return num*2-1;
    }
    else
    {
        return num-1;
    }
}


int main()
{
    file_in_out();

    int t;
    cin>>t;

    while(t--)
    {
        ll l,r;
        cin>>l>>r;
        cout<<query(l,r)<<endl;;
    }


}