因为不会用索引就用了链表

#include<bits/stdc++.h>
using namespace std;

struct node{
    int val;
    node *pre,*nxt;
}*head,*tail,*p;

signed main(){
    unsigned long long n,k;
    cin >> n >> k;
    unsigned long long tmp=1<<n;
    unsigned long long num;
    num = k^(k>>1);
    
    bitset<64>binarry(num);
    head = new node;
    p = head;
    head->pre = NULL;
    
    for(int i = 0;i<n;i++){
         
        tail = new node;
        tail->val = binarry[i];
        tail->pre = p;
        p->nxt = tail;    
        p = tail;
    }
    p->nxt = NULL;
    while(p->pre!=NULL){
         cout << p->val;
         p = p->pre;
    }
}