[RT](https://from.blog.luogu.org/solution-p5657)
by ____蒟蒻____ @ 2019-11-16 17:35:30
1ull<<n，看到这句话我就知道您一定会当场去世
by tzc_wk @ 2019-11-16 17:43:54
[RT](https://www.luogu.org/blog/zyy-2006/solution-p5657)
by zyy121212 @ 2019-11-16 17:45:36
@[ET2006](/user/115194) 1ull<<n这句话出现在哪行……
by mcendu @ 2019-11-16 17:49:34
[RT](https://www.luogu.org/blog/yltx/solution-p5657)
by 引领天下 @ 2019-11-16 17:51:25
@[ET2006](/user/115194) 为啥要用ull啊，降到1<<63不就完事了。
by 引领天下 @ 2019-11-16 17:51:42
@[Creator](/user/88551) nb
by happyZYM @ 2019-11-16 18:35:13
```cpp
#include<bits/stdc++.h>
using namespace std;
string getcode(int n,unsigned long long k)
{
if (n==1)
{
if (k==0)
return "0";
else
return "1";
}
if (k<(unsigned long long)pow(2,n-1))
return "0"+getcode(n-1,k);
else
{
return "1"+getcode(n-1,(unsigned long long)pow(2,n)-(unsigned long long)k-(unsigned long long)1);
cout<<k<<endl;
}
}
int main()
{
int n;
unsigned long long k;
cin>>n>>k;
cout<<getcode(n,k)<<endl;
return 0;
}
```
by twentyaurora @ 2019-11-16 18:53:40