BitwiseAND.cpp

// Question from hackerrank
// Solution by Isla, Joe, and Lyn

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int N = 0;
    cin >> N;
    for (int i = 0; i < N; i++)
    {
        long a,b;
        cin >> a;
        cin >> b;

        long delta = b - a;
        long sequenceLen = log2(delta)+1;

        long aShift = a >> sequenceLen;
        long bShift = b >> sequenceLen;
        long v = aShift;
        for (long j = aShift+1; j <= bShift; j++)
        {
            v = v & j;
        }
        v = v << sequenceLen;
        cout << v << endl;
    }
    return 0;
}