#include "doll.h"
#include <bits/stdc++.h>
#define fr first
#define sc second
#define pii pair<int, int>
using namespace std;
int N, M, S;
vector <int> A, C, X, Y;
struct less_equal_2 {
vector <int> cnt;
less_equal_2() {
cnt.resize((int)1e5 + 5, 0);
}
bool need() {
bool ok = 1;
for (int i = 1; i <= N; i++) {
cnt[A[i]]++;
}
for (int i = 1; i <= M; i++) {
ok &= (cnt[i] <= 2);
}
return ok;
}
struct Para {
int trigger, switcher;
Para (int trigger_, int switcher_) {
trigger = trigger_;
switcher = switcher_;
}
Para () {
trigger = -1;
switcher = -1;
}
};
void solve() {
vector <int> pos(M + 5, 0);
vector <pii> twice(M + 5, {-1, -1});
for (int i = 1; i <= N; i++) {
if (!pos[A[i]]) {
twice[A[i]].fr = i;
} else {
twice[A[i]].sc = i;
}
pos[A[i]] = i;
}
int id = -1;
int siz = 0;
C[0] = A[1];
vector <Para> vec;
for (int i = 1; i <= M; i++) {
if (cnt[i] == 0) {
continue;
}
if (cnt[i] == 1) {
int nxt = (pos[i] < N ? A[pos[i] + 1] : 0);
C[i] = nxt;
}
if (cnt[i] == 2) {
C[i] = id--, siz++;
vec.push_back(Para(i, C[i]));// our trigger and his switcher
}
}
X.resize(siz);
Y.resize(siz);
for (auto el : vec) {
int id = (-el.switcher) - 1;
X[id] = A[twice[el.trigger].fr + 1];
if (twice[el.trigger].sc == N) {
Y[id] = 0;
} else {
Y[id] = A[twice[el.trigger].sc + 1];
}
}
}
}subtask2;
// A - sequance
// C - edges of triggers
// X/Y - edges of switches
// M - triggers vertexes
void create_circuit(int MM, vector<int> AA) {
M = MM;
N = AA.size();
A.resize(N + 1);
A[0] = 0;
for (int i = 0; i < N; i++) {
A[i + 1] = AA[i];
}
C.resize(M + 1);
if (subtask2.need()) {
subtask2.solve();
}
answer(C, X, Y);
}
