Problem: 2052A - Adrenaline Rush
Language: C++20 (GCC 13-64)

Previous submission (verdict: Wrong answer on test 4):
#include <iostream>
#include <bits/stdc++.h>
// #include <sys/resource.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
// using namespace chrono;
using namespace __gnu_pbds;
template <typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

template <typename T>
using omset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

template <typename T, typename R> using o_map = tree<T, R, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

// Pragmas
#pragma GCC optimize("O3,unroll-loops")
// #ifndef LOCAL_PROJECT
// #pragma GCC target("avx2")
// #endif
//#pragma GCC optimize("Ofast")

// Speed
inline void FastIO()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

// Aliases
using ll = long long;
using lld = long double;
using ull = unsigned long long;

// Constants
const lld pi = 3.141592653589793238;
const ll INF = LONG_LONG_MAX;
const ll mod = 1e9 + 7;

// TypeDEf
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;
typedef vector<string> vs;
typedef unordered_map<ll, ll> umll;
typedef map<ll, ll> mll;

// Macros
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define fl(i, n) for (ll i = 0; i < n; i++)
#define fls(i, m, n) for (ll i = m; i <= n; i++)
#define rl(i, m, n) for (ll i = n; i >= m; i--)
#define py cout << "YES\n";
#define pm cout << "-1\n";
#define pn cout << "NO\n";
#define vr(v) v.begin(), v.end()
#define rv(v) v.rbegin(), v.rend()
#define edl '\n'
#define len(v) v.size()
#define nl cout << edl;

// Debug
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '"' << x << '"'; }
void __print(const string &x) { cerr << '"' << x << '"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }

template <typename T, typename V>
void __print(const pair<T, V> &x)
{
    cerr << '{';
    __print(x.first);
    cerr << ',';
    __print(x.second);
    cerr << '}';
}
template <typename T>
void __print(const T &x)
{
    int f = 0;
    cerr << '{';
    for (auto &i : x)
        cerr << (f++ ? "," : ""), __print(i);
    cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v)
{
    __print(t);
    if (sizeof...(v))
        cerr << ", ";
    _print(v...);
}
#ifndef ONLINE_JUDGE
#define debug(x...)               \
    cerr << "[" << #x << "] = ["; \
    _print(x)
#else
#define debug(x...)
#endif

// Operator overloads
template <typename T1, typename T2> // cin >> pair<T1, T2>
istream &operator>>(istream &istream, pair<T1, T2> &p)
{
    return (istream >> p.first >> p.second);
}
template <typename T> // cin >> vector<T>
istream &operator>>(istream &istream, vector<T> &v)
{
    for (auto &it : v)
        cin >> it;
    return istream;
}
template <typename T1, typename T2> // cout << pair<T1, T2>
ostream &operator<<(ostream &ostream, const pair<T1, T2> &p)
{
    return (ostream << p.first << " " << p.second);
}
template <typename T> // cout << vector<T>
ostream &operator<<(ostream &ostream, const vector<T> &c)
{
    for (auto &it : c)
        cout << it << " ";
    return ostream;
}

// Utility functions
#define print(x) cout << x << '\n'

template <typename T>
ll sumvec(vector<T> v)
{
    ll n = v.size();
    ll s = 0;
    fl(i, n) s += v[i];
    return s;
}


mt19937 rng;
int getRandomNumber(int l, int r)
{
    uniform_int_distribution<int> dist(l, r);
    return dist(rng);
}

void preSolve()
{
    rng = mt19937(chrono::steady_clock::now().time_since_epoch().count());
    // allocateStackMax();
}

// Code
void solve()
{

    ll n;
    cin >> n ;
    //ll m;
    //cin >> m;
    vll v(n);
    cin >> v;

    vpll ans;
    fl(i, n){
        set<pll >s1;
        fls(j, i + 1, n - 1){
            if(v[i] > v[j]){
                s1.insert({v[i], v[j]});
            }
        }
        for(auto it : s1){
            ans.pb(it);
            // debug("s1", it);
        }
        
        // debug(v[i], ans);
    }
    fl(i, n){
        set<pll >s2;
        fls(j, i + 1, n - 1){
            
            if(v[i] < v[j]){
                s2.insert({v[j], v[i]});
            }
        }
        
        for(auto it : s2){
            ans.pb(it);
            // debug("s2", it);
        }
        vpll v1;
        for(auto it : s2){
            v1.pb({it.ss, it.ff});
            
        }
        for(auto it : v1){
            ans.pb(it);
            // debug("v1", it);
        }
        // debug(v[i], ans);
    }
    print(len(ans));
    for(auto it : ans){
        print(it);
    }
}
// Main
signed main()
{
// #ifndef ONLINE_JUDGE
//     freopen("Error.txt", "w", stderr);
// #endif
    FastIO();
    preSolve();
    ll t=1;
    //cin >> t;
    fl(i, t)
    {
        solve();
    }
    // solve();
    // fl(i,t) //Kickstart
    // {
    //     cout<<"Case #"<<i+1<<": ";
    //     solve();
    //     cout<<"\n";
    // }
    return 0;
}
// End

Submission (verdict: Wrong answer on test 5):
#include <iostream>
#include <bits/stdc++.h>
// #include <sys/resource.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
// using namespace chrono;
using namespace __gnu_pbds;
template <typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

template <typename T>
using omset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

template <typename T, typename R> using o_map = tree<T, R, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

// Pragmas
#pragma GCC optimize("O3,unroll-loops")
// #ifndef LOCAL_PROJECT
// #pragma GCC target("avx2")
// #endif
//#pragma GCC optimize("Ofast")

// Speed
inline void FastIO()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

// Aliases
using ll = long long;
using lld = long double;
using ull = unsigned long long;

// Constants
const lld pi = 3.141592653589793238;
const ll INF = LONG_LONG_MAX;
const ll mod = 1e9 + 7;

// TypeDEf
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;
typedef vector<string> vs;
typedef unordered_map<ll, ll> umll;
typedef map<ll, ll> mll;

// Macros
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define fl(i, n) for (ll i = 0; i < n; i++)
#define fls(i, m, n) for (ll i = m; i <= n; i++)
#define rl(i, m, n) for (ll i = n; i >= m; i--)
#define py cout << "YES\n";
#define pm cout << "-1\n";
#define pn cout << "NO\n";
#define vr(v) v.begin(), v.end()
#define rv(v) v.rbegin(), v.rend()
#define edl '\n'
#define len(v) v.size()
#define nl cout << edl;

// Debug
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '"' << x << '"'; }
void __print(const string &x) { cerr << '"' << x << '"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }

template <typename T, typename V>
void __print(const pair<T, V> &x)
{
    cerr << '{';
    __print(x.first);
    cerr << ',';
    __print(x.second);
    cerr << '}';
}
template <typename T>
void __print(const T &x)
{
    int f = 0;
    cerr << '{';
    for (auto &i : x)
        cerr << (f++ ? "," : ""), __print(i);
    cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v)
{
    __print(t);
    if (sizeof...(v))
        cerr << ", ";
    _print(v...);
}
#ifndef ONLINE_JUDGE
#define debug(x...)               \
    cerr << "[" << #x << "] = ["; \
    _print(x)
#else
#define debug(x...)
#endif

// Operator overloads
template <typename T1, typename T2> // cin >> pair<T1, T2>
istream &operator>>(istream &istream, pair<T1, T2> &p)
{
    return (istream >> p.first >> p.second);
}
template <typename T> // cin >> vector<T>
istream &operator>>(istream &istream, vector<T> &v)
{
    for (auto &it : v)
        cin >> it;
    return istream;
}
template <typename T1, typename T2> // cout << pair<T1, T2>
ostream &operator<<(ostream &ostream, const pair<T1, T2> &p)
{
    return (ostream << p.first << " " << p.second);
}
template <typename T> // cout << vector<T>
ostream &operator<<(ostream &ostream, const vector<T> &c)
{
    for (auto &it : c)
        cout << it << " ";
    return ostream;
}

// Utility functions
#define print(x) cout << x << '\n'

template <typename T>
ll sumvec(vector<T> v)
{
    ll n = v.size();
    ll s = 0;
    fl(i, n) s += v[i];
    return s;
}


mt19937 rng;
int getRandomNumber(int l, int r)
{
    uniform_int_distribution<int> dist(l, r);
    return dist(rng);
}

void preSolve()
{
    rng = mt19937(chrono::steady_clock::now().time_since_epoch().count());
    // allocateStackMax();
}

// Code
void solve()
{

    ll n;
    cin >> n ;
    //ll m;
    //cin >> m;
    vll v(n);
    cin >> v;

    vpll ans;
    fl(i, n){
        set<pll >s1;
        fls(j, i + 1, n - 1){
            if(v[i] > v[j]){
                s1.insert({v[i], v[j]});
            }
        }
        for(auto it : s1){
            ans.pb(it);
            // debug("s1", it);
        }
        
        // debug(v[i], ans);
    }
    fl(i, n){
        set<pll >s2;
        fls(j, i + 1, n - 1){
            
            if(v[i] < v[j]){
                s2.insert({v[j], v[i]});
            }
        }
        
        for(auto it : s2){
            ans.pb(it);
            // debug("s2", it);
        }
        vpll v1;
        for(auto it : s2){
            v1.pb({it.ss, it.ff});
            
        }
        reverse(vr(v1));
        for(auto it : v1){
            ans.pb(it);
            // debug("v1", it);
        }
        // debug(v[i], ans);
    }
    print(len(ans));
    for(auto it : ans){
        print(it);
    }
}
// Main
signed main()
{
// #ifndef ONLINE_JUDGE
//     freopen("Error.txt", "w", stderr);
// #endif
    FastIO();
    preSolve();
    ll t=1;
    //cin >> t;
    fl(i, t)
    {
        solve();
    }
    // solve();
    // fl(i,t) //Kickstart
    // {
    //     cout<<"Case #"<<i+1<<": ";
    //     solve();
    //     cout<<"\n";
    // }
    return 0;
}
// End