Sorting

#include <bits/stdc++.h>
using namespace std;
// #define cerr if(false) cerr
#define watch(x) cerr << (#x) << " is " << (x) << endl;
#define endl '\n'
#define ld long double
#define int long long
#define pii pair<int, int>
#define fi first
#define se second
#define sz(a) (int)(a).size()
#define y1 lsdjkfhshfdsighoihweogihewoghi
#define all(x) (x).begin(), (x).end()
 
const int maxn = 10;
int n;
set<vector<int>> vis[10];
 
map<vector<int>, vector<int>> par;
 
void solve() {
    cin >> n;
 
    vector<int> a;
    for(int i = 1; i <= n; i++) {
        int x;
        cin >> x;
 
        a.push_back(x);
    }    
    
    if(n <= 8) {

        if(vis[n].count(a)) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    } else {
        int inv = 0;
        for(int i = 0; i < n; i++) {
            for(int j = i+1; j < n; j++) {
                if(a[i] > a[j]) inv++;
            }
        }

        if(inv % 2 == 0) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }
}
 
 
 
signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
 
    for(int len = 1; len <= 8; len++) {
            vector<int> a;
            for(int i = 1; i <= len; i++) {
                a.push_back(i);
            }    
 
            vector<int> orig = a;
        
            queue<vector<int>> Q;
            Q.push(a);
            vis[len].emplace(a);
        
            while(!Q.empty()) {
                vector<int> v = Q.front(); Q.pop();
        
                for(int i = 0; i+1 < sz(v); i++) {
                    for(int j = i+2; j+1 < sz(v); j++) {
                        vector<int> cpy = v;
                        swap(v[i], v[j]);
                        swap(v[i+1], v[j+1]);
        
                        if(!vis[len].count(v)) {
                            par[v] = cpy;
                            Q.push(v);
                            vis[len].emplace(v);
                        }
                        swap(v[i], v[j]);
                        swap(v[i+1], v[j+1]);
                    }
                }
            }
    }
 
    int t;
    cin >> t;
 
    while(t--) solve();
}
 
/*
40 320 000
 
322 560 000
*/
 
// Did you read the bounds?
// Did you make typos?
// Are there edge cases (N=1?)
// Are array sizes proper?
// Integer overflow?
// DS reset properly between test cases?
// Is using long longs causing TLE?
// Are you using floating points?

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED