Submission #1053990

#	Time	Username	Problem	Language	Result	Execution time	Memory
1053990		huutuan	Secret Permutation (RMI19_permutation)	C++14	20 / 100	30 ms	344 KiB

permutation

#include "permutation.h"

#include <bits/stdc++.h>

using namespace std;

mt19937 rng(69420);

int rand(int l, int r){
   return uniform_int_distribution<int>(l, r)(rng);
}

void solve(int n) {
   if (n==3){
      if (query({1, 2, 3})==2) answer({1, 2, 3});
      if (query({2, 1, 3})==2) answer({2, 1, 3});
      answer({3, 1, 2});
   }
   vector<int> ans(n+1, -1);
   while (1){
      int x=rand(1, n);
      int y=x;
      while (y==x) y=rand(1, n);
      if (x>y) swap(x, y);
      map<int, int> cnt;
      vector<int> dd(n+1);
      for (int i=1; i<=n; ++i) if (i!=x && i!=y){
         vector<int> v;
         v.push_back(i);
         v.push_back(x);
         for (int j=1; j<=n; ++j) if (j!=i && j!=x && j!=y) v.push_back(j);
         v.push_back(y);
         int d=query(v);
         v.erase(v.begin());
         v.push_back(i);
         d-=query(v);
         ++cnt[d];
         dd[i]=d;
      }
      for (auto &j:cnt) if (j.second>=2){
         int diff=abs(j.first);
         ans[x]=cnt[-diff]+1;
         ans[y]=n-cnt[diff];
         int px=y;
         for (int k=1; k<=n; ++k) if (k!=x && k!=y && abs(dd[k])!=diff){
            ans[k]=(dd[k]+ans[x]+ans[y])/2;
            if (ans[k]==ans[x]+1) px=k;
         }
         for (int k=1; k<=n; ++k) if (ans[k]==-1){
            vector<int> v;
            v.push_back(k);
            v.push_back(y);
            v.push_back(x);
            for (int l=1; l<=n; ++l) if (l!=k && l!=x && l!=y) v.push_back(l);
            int dx=query(v);
            swap(v[0], v[1]);
            dx-=query(v);
            dx=abs(ans[x]-ans[y])-dx;
            v.clear();
            v.push_back(k);
            v.push_back(x);
            v.push_back(px);
            for (int l=1; l<=n; ++l) if (l!=k && l!=px && l!=x) v.push_back(l);
            int dx1=query(v);
            swap(v[0], v[1]);
            dx1-=query(v);
            dx1=abs(ans[px]-ans[x])-dx1;
            if (dx<dx1){
               ans[k]=ans[x]-dx;
            }else{
               ans[k]=ans[x]+dx;
            }
         }
         ans.erase(ans.begin());
         answer(ans);
      }
   }
}

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: 3 / 15
• Subtask 2: 7 / 35
• Subtask 3: 10 / 50