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Submission #945236

# Submission time Handle Problem Language Result Execution time Memory
945236 2024-03-13T14:48:21 Z vjudge1 Secret Permutation (RMI19_permutation) C++17
100 / 100
 706 ms 452 KB 
#include <bits/stdc++.h>

#include "permutation.h"
using namespace std;

mt19937 rng(1234);

#define next amongus
pair<int, int> next[434];
int p[333];
int n;
vector<int> id;

void output() {
        vector<int> res(n);
        for (int i = 1; i <= n; i++) res[p[i] - 1] = i;
        answer(res);
        return;
}

bool Try(int i, int index, int cur) {
        int x = next[index].first;
        int d = next[index].second;
        if (i == n - 1) {
                if (cur + d <= n && p[cur + d] == x) return output(), 1;
                if (cur - d >= 1 && p[cur - d] == x) return output(), 1;
                return 0;
        }

        int random = rng() & 1;
        int t = 2;
        while (t--) {
                if (random) {
                        if (cur + d <= n && p[cur + d] == 0) {
                                p[cur + d] = x;
                                if (Try(i + 1, x, cur + d)) return 1;
                                p[cur + d] = 0;
                        }
                } else {
                        if (cur - d >= 1 && p[cur - d] == 0) {
                                p[cur - d] = x;
                                if (Try(i + 1, x, cur - d)) return 1;
                                p[cur - d] = 0;
                        }
                }
                random ^= 1;
        }
        return 0;
}

void solve(int N) {
        n = N;
        id = vector<int>(N);
        iota(id.begin(), id.end(), 1);
        shuffle(id.begin(), id.end(), rng);
        vector<int> a(N);
        for (int i = 0; i < N; i++) {
                a[i] = query(id);
                id.emplace_back(id[0]);
                id.erase(id.begin());
        }
        int64_t sum = accumulate(a.begin(), a.end(), 0ll);
        sum /= N - 1;
        for (int i = 0; i < N; i++) {
                /// diff between p[id[i]] and p[id[i - 1]]
                next[id[i]] = {(id[i ? i - 1 : N - 1]), sum - a[i]};
        }
        for (int i = 1; i <= N; i++) {
                /// try p[id[0]] = i;
                p[i] = id[0];
                if (Try(0, id[0], i)) break;
                p[i] = 0;
        }
}

Compilation message

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
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 344 KB Output is correct

Subtask #2
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 344 KB Output is correct
7 Correct 1 ms 444 KB Output is correct
8 Correct 1 ms 344 KB Output is correct
9 Correct 1 ms 448 KB Output is correct
10 Correct 1 ms 344 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 1 ms 344 KB Output is correct
13 Correct 1 ms 444 KB Output is correct
14 Correct 1 ms 344 KB Output is correct
15 Correct 1 ms 344 KB Output is correct
16 Correct 1 ms 344 KB Output is correct

Subtask #3
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 344 KB Output is correct
7 Correct 1 ms 444 KB Output is correct
8 Correct 1 ms 344 KB Output is correct
9 Correct 1 ms 448 KB Output is correct
10 Correct 1 ms 344 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 1 ms 344 KB Output is correct
13 Correct 1 ms 444 KB Output is correct
14 Correct 1 ms 344 KB Output is correct
15 Correct 1 ms 344 KB Output is correct
16 Correct 1 ms 344 KB Output is correct
17 Correct 10 ms 452 KB Output is correct
18 Correct 12 ms 452 KB Output is correct
19 Correct 10 ms 452 KB Output is correct
20 Correct 246 ms 448 KB Output is correct
21 Correct 7 ms 452 KB Output is correct
22 Correct 183 ms 452 KB Output is correct
23 Correct 54 ms 444 KB Output is correct
24 Correct 706 ms 448 KB Output is correct
25 Correct 7 ms 452 KB Output is correct
26 Correct 97 ms 452 KB Output is correct