Submission #953147

#	Time	Username	Problem	Language	Result	Execution time	Memory
953147		vjudge1	Secret Permutation (RMI19_permutation)	C++17	100 / 100	43 ms	596 KiB

permutation

#include <iostream>
#include <random>
#include <algorithm>
#include <vector>
#include <cmath>

typedef long long ll;
typedef double lf;

// #define DEBUG 1

using namespace std;

const int MAXN = 300, B = 258;

#ifndef DEBUG

#include "permutation.h"

#endif

#ifdef DEBUG

namespace LOCAL
{
    int n, a[MAXN], q;
    inline void Solve()
    {
        cin >> n, q = 0;
        for (int i = 1; i <= n; i++) cin >> a[i];
    }
}

int query(vector <int> p)
{
    if (p.size() != LOCAL::n) {cout << "Query too short.\n"; exit(0);}
    LOCAL::q++;
    int sum = 0;
    for (int i = 0; i < LOCAL::n - 1; i++) sum += abs(LOCAL::a[p[i]] - LOCAL::a[p[i + 1]]);
    cout << "Query:\n";
    for (int i = 0; i < LOCAL::n; i++) cout << p[i] << ' '; cout << '\n';
    cout << sum << "\n";
    return sum;
}

void answer(vector <int> p)
{
    if (p.size() != LOCAL::n) {cout << "Answer too short.\n"; exit(0);}
    cout << "Queries used: " << LOCAL::q << "\n";
    for (int i = 0; i < LOCAL::n; i++) cout << p[i] << ' '; cout << '\n';
    exit(0);
}

void solve(int N);

int main()
{
    freopen("B.in", "r", stdin);
    freopen("B.out", "w", stdout);
    LOCAL::Solve();
    solve(LOCAL::n);
    return 0;
}

#endif

mt19937 Rand(102934);

int n, idx[MAXN], a[MAXN], d[MAXN];
vector <int> qry;

int ans[MAXN], rt;
bool vis[MAXN << 1];
inline bool Solve(int cur, int p, int l, int r)
{
    if (r - l > n - 1 || vis[p + B]) return 0;
    if (cur == n)
    {
        ans[cur] = p;
        if (p + d[n] == 0 || p - d[n] == 0) return rt = l, 1;
        return 0;
    }
    vis[p + B] = 1, ans[cur] = p;
    if (Solve(cur + 1, p + d[cur], l, max(r, p + d[cur]))) return 1;
    if (Solve(cur + 1, p - d[cur], min(l, p - d[cur]), r)) return 1;
    vis[p + B] = 0;
    return 0;
}

void solve(int N)
{
    n = N;
    for (int i = 1; i <= n; i++) idx[i] = i;
    for (int i = 1; i <= n; i++) swap(idx[i], idx[Rand() % n + 1]);
    qry.clear();
    for (int i = 1; i <= n; i++) qry.push_back(idx[i]);
    a[0] = query(qry);
    int sum = 0;
    for (int i = 1; i <= n - 1; i++)
    {
        qry.clear();
        for (int j = i; j >= 1; j--) qry.push_back(idx[j]);
        for (int j = n; j > i; j--) qry.push_back(idx[j]);
        a[i] = query(qry), sum += a[i];
    }
    sum -= (n - 2) * a[0], sum /= n - 1;
    d[n] = sum;
    for (int i = 1; i <= n - 1; i++) d[i] = a[0] - a[i] + d[n];
    Solve(1, 0, 0, 0);
    qry.resize(n);
    qry[idx[1] - 1] = 1 - rt;
    for (int i = 2; i <= n; i++) qry[idx[i] - 1] = qry[idx[1] - 1] + ans[i];
    answer(qry);
}

Compilation message (stderr)

stub.cpp: In function 'int query(int*)':
stub.cpp:15:9: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |   fscanf(stdin, "%d", &x);
      |   ~~~~~~^~~~~~~~~~~~~~~~~
stub.cpp: In function 'int main(int, char**)':
stub.cpp:48:9: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |   fscanf(stdin, "%d", &N);
      |   ~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 50 / 50