Submission #523540

#	Time	Username	Problem	Language	Result	Execution time	Memory
523540		Farhan_HY	Cat (info1cup19_cat)	C++14	0 / 100	69 ms	320 KiB

cat

#include <bits/stdc++.h>
#define int long long
#define float double
#define pb push_back
#define F first
#define S second
#define T int t; cin >> t; while(t--)
#define IOS ios::sync_with_stdio(); cin.tie(0); cout.tie(0);

using namespace std;

const int inf = 8e18;
const int N = 1e6 + 6;
const int M = 1e3 + 3;
const int mod = 1e9 + 7;
const float pi = atan(1) * 4;
int a[N];
int n, m;
map<int, int> Pos;
vector<pair<int, int>> v;

void Swap(int i, int p)
{
    swap(Pos[a[i]], Pos[a[p]]);
    swap(a[i], a[p]);
    v.pb({i, p});
    swap(Pos[a[n - p + 1]], Pos[a[n - p + 1]]);
    swap(a[n - i + 1], a[n - p + 1]);
}

main()
{
    T
    {
        v.clear();
        Pos.clear();
        cin >> n;
        for(int i = 0; i < n ; i++)
            cin >> a[i], Pos[a[i]] = i + 1;
        for(int i = 0; i < n / 2; i++)
        {
            int p = Pos[i];
            if (a[i] == i)
                continue;
            if (p < n / 2)
                Swap(i, p);
            else
            {
                if (n - p - 1 == i)
                {
                    Swap(i, i + 1);
                    Swap(i, p);
                }
                else
                    Swap(i, p);
            }
        }
        bool ok = true;
        for(int i = 1; i <= n; i++)
            ok &= a[i] >= a[i - 1];
        if (!ok)
        {
            cout << "-1\n";
            continue;
        }
        cout << v.size() << ' ' << v.size() << '\n';
        for(auto x: v)
            cout << x.F << ' ' << x.S << '\n';
    }
}

Compilation message (stderr)

cat.cpp:31:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   31 | main()
      | ^~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 10
• Subtask 3: 0 / 25
• Subtask 4: 0 / 15
• Subtask 5: 0 / 35