Sorting

#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define per(i, a, b) for (int i = a - 1; i >= (b); --i)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back

#define umap unordered_map
#define uset unordered_set
#define INF 1000000000

typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long long ll;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(NULL);

    uset<string> vis;
    int tc, n;
    cin >> tc;
    while (tc--) {
        cin >> n;
        string nums(n, 0);
        rep(i, 0, n) cin >> nums[i];

        queue<pair<string, int>> q;
        q.emplace(nums, 0);
        vis.insert(nums);
        string ans = "NO", goal = string(n, ' ');
        rep(i, 0, n) goal[i] = '1' + i;

        while (!q.empty()) {
            int dist;
            tie(nums, dist) = q.front();
            q.pop();
            if (nums == goal) {
                ans = "YES";
                while (!q.empty()) q.pop();
                continue;
            }
            if (dist++ >= 300) continue;

            rep(i, 0, n - 3) {
                string next;
                rep(j, i + 2, n - 1) {
                    next = nums;
                    swap(next[i], next[j]);
                    swap(next[i + 1], next[j + 1]);
                    if (!vis.count(next)) {
                        vis.insert(next);
                        q.emplace(next, dist);
                    }
                }
            }
        }

        cout << ans << '\n';
        vis.clear();
    }
    return 0;
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED