题解 | #光之屏障#
光之屏障
https://ac.nowcoder.com/acm/contest/11219/B
B.从2的0次方开始枚举,直到2的i次方大于左端点l判断是否大于右端点即可
#include<bits/stdc++.h>
using namespace std;
int n;
int main()
{
cin>>n;
while(n--)
{
int x,y;
cin>>x>>y;
int i;
for(i = 0;1<<i<x;i++);
if(1<<i>y) cout<<"-1"<<endl;
else cout<<(1<<i)<<endl;
}
return 0;
}