题解(法兰西大佬加缩进)

#include <iostream>
using namespace std;
typedef unsigned long long ull;
ull n, k;
void f(ull n, ull k) {
	if(n==1){
		cout<<k;
	return;
	}ull mid = (1UL<<(n-1))-1;
	if(k<=mid) {
		cout<<0;
		f(n-1, k);
	} else {
		cout<<1;
		f(n-1, mid-k+mid+1);
	}
}
int main() {
	cin>>n>>k;
	f(n, k);
	cout<<endl;
	return 0;
}