oj.uz

Submission #634024

# Submission time Handle Problem Language Result Execution time Memory
634024 2022-08-23T17:19:22 Z boris_mihov Cat (info1cup19_cat) C++17
33.75 / 100
 413 ms 28156 KB 
#include <algorithm>
#include <iostream>
#include <numeric>
#include <vector>

typedef long long llong;
const int MAXN = 100000 + 10;
const int INF  = 1e9;

int n, m;
int a[MAXN];
int posOf[MAXN];
std::vector < std::pair <int,int> > ops;
inline void operation(int x, int y)
{
    std::swap(a[x], a[y]);
    std::swap(a[n-x+1], a[n-y+1]);
    posOf[a[x]] = x;
    posOf[a[y]] = y;
    posOf[a[n-x+1]] = n-x+1;
    posOf[a[n-y+1]] = n-y+1;
    ops.emplace_back(x, y);
}

void solve()
{
    int cnt = 0;
    ops.clear();
    for (int i = 1 ; i <= n ; ++i)
    {
        if (a[n - i + 1] != n - a[i] + 1)
        {
            std::cout << -1 << '\n';
            return;
        }

        posOf[a[i]] = i;
        if (i <= n/2)
        {
            cnt += (a[i] > n/2);
        }
    }

    if (cnt & 1)
    {
        std::cout << -1 << '\n';
        return;
    }

    for (int i = 1 ; i <= n/2 ; ++i)
    {
        if (a[i] <= n/2) continue;
        int wantedSwap = n-a[i]+1;
        if (i != wantedSwap && a[wantedSwap] > n/2)
        {
            operation(i, n - wantedSwap + 1);
        }
    }

    int lastBig = 0;
    for (int i = 1 ; i <= n/2 ; ++i)
    {
        if (a[i] <= n/2) continue;
        if (lastBig != 0)
        {
            operation(i, n - lastBig + 1);
            lastBig = 0;
        } else
        {
            lastBig = i;
        }
    }

    for (int i = 1 ; i <= n ; ++i)
    {
        if (posOf[i] != i)
        {
            operation(i, posOf[i]);
        }
    }

    for (int i = 1 ; i <= n ; ++i)
    {
        if (a[i] != i)
        {
            std::cout << -1 << '\n';
            return;
        }
    }

    std::cout << ops.size() << ' ' << ops.size() << '\n';
    for (auto [x, y] : ops)
    {
        std::cout << x << ' ' << y << '\n';
    }
}

void read()
{
    std::cin >> n;
    for (int i = 1 ; i <= n ; ++i)
    {
        std::cin >> a[i];
    }
}

void fastIO()
{
    std::ios_base :: sync_with_stdio(0);
    std::cout.tie(nullptr);
    std::cin.tie(nullptr);
}

int tests;
int main()
{
    fastIO();
    std::cin >> tests;
    
    while (tests--)
    {
        read();
        solve();
    }

    return 0;
}

Subtask #1
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 340 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 1008 KB Output is correct
2 Correct 18 ms 1028 KB Output is correct

Subtask #3
8.75 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 340 KB Output is correct
2 Correct 23 ms 1008 KB Output is correct
3 Correct 18 ms 1028 KB Output is correct
4 Partially correct 19 ms 1100 KB Valid reconstruction
5 Partially correct 8 ms 596 KB Valid reconstruction
6 Partially correct 7 ms 536 KB Valid reconstruction

Subtask #4
0.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 1008 KB Output is correct
2 Correct 18 ms 1028 KB Output is correct
3 Correct 413 ms 28156 KB Output is correct
4 Incorrect 166 ms 13644 KB Wrong answer
5 Halted 0 ms 0 KB -

Subtask #5
0.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 340 KB Output is correct
2 Correct 23 ms 1008 KB Output is correct
3 Correct 18 ms 1028 KB Output is correct
4 Partially correct 19 ms 1100 KB Valid reconstruction
5 Partially correct 8 ms 596 KB Valid reconstruction
6 Partially correct 7 ms 536 KB Valid reconstruction
7 Correct 413 ms 28156 KB Output is correct
8 Incorrect 166 ms 13644 KB Wrong answer
9 Halted 0 ms 0 KB -