#include <bits/stdc++.h>
#include "doll.h"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define fi first
#define se second
#define mp make_pair
int n;
const int N = (int)2e5 + 10;
int x[N], y[N];
int flip[N];
int id = 1;
int p = 1;
int build(int l, int r){
if(l >= r) return 0;
if(r + n <= p - 1) return -1;
int cur = id++;
int mid = (l + r) / 2;
x[cur] = build(l, mid);
y[cur] = build(mid + 1, r);
return -cur;
}
void put(int xv){
int cur = -1;
int real;
int nx;
while(1){
real = -cur;
if(flip[real]){
nx = y[real];
flip[real] = false;
if(nx == 0){
y[real] = xv;
return;
}
else{
cur = nx;
}
}
else{
nx = x[real];
flip[real] = true;
if(nx == 0){
x[real] = xv;
return;
}
else{
cur = nx;
}
}
}
}
void create_circuit(int M, vector<int> A) {
n = A.size();
while(p < n)
p *= 2;
build(0, p - 1);
vector<int> C(M + 1);
C[0] = A[0];
for(int i = 1; i <= M; i ++ )
C[i] = -1;
for(int i = 1; i < n ; i ++ )
put(A[i]);
if(n % 2 == 1)
put(-1);
put(0);
vector<int> xx, yy;
for(int i = 1; i < id; i ++ ){
xx.push_back(x[i]);
yy.push_back(y[i]);
}
answer(C, xx, yy);
}
