Submission #1054126

#	Time	Username	Problem	Language	Result	Execution time	Memory
1054126		huutuan	Secret Permutation (RMI19_permutation)	C++14	62.43 / 100	14 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) {
   vector<int> ans(n+1);
   vector<int> v(n);
   iota(v.begin(), v.end(), 1);
   vector<int> d1(n+1);
   for (int i=0; i<n; ++i){
      d1[v[0]]=query(v);
      rotate(v.begin(), v.begin()+1, v.end());
   }
   int sum=accumulate(d1.begin(), d1.end(), 0)/(n-1);
   for (int &i:d1) i=sum-i;
   auto find=[&](int x, int y){
      if (x>y) swap(x, y);
      if (y-x==1) return d1[y];
      if (y-x==n-1) return d1[1];
      vector<int> vv(n);
      iota(vv.begin(), vv.end(), 1);
      rotate(vv.begin(), vv.begin()+x-1, vv.end());
      reverse(vv.begin(), vv.begin()+y-x);
      int s=query(vv);
      for (int i=1; i<n; ++i){
         if (abs(vv[i]-vv[i-1])==1){
            s-=d1[max(vv[i], vv[i-1])];
         }else if (abs(vv[i]-vv[i-1])==n-1){
            s-=d1[1];
         }
      }
      return s;
   };
   int d13=find(1, 3);
   if (d1[2]+d1[3]==d13){
      ans[2]=ans[1]+d1[2];
      ans[3]=ans[2]+d1[3];
   }else if (d1[2]+d13==d1[3]){
      ans[1]=ans[2]+d1[2];
      ans[3]=ans[1]+d13;
   }else{
      ans[3]=ans[1]+d13;
      ans[2]=ans[3]+d1[3];
   }
   for (int i=4; i<=n; ++i){
      int t1=ans[i-1]+d1[i];
      int t2=ans[i-1]-d1[i];
      if (abs(t1-ans[i-2])==find(i-2, i)) ans[i]=t1;
      else ans[i]=t2;
   }
   ans.erase(ans.begin());
   int mn=*min_element(ans.begin(), ans.end());
   for (int &i:ans) i-=mn-1;
   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: 10.71429 / 15
• Subtask 2: 21.56 / 35
• Subtask 3: 30.15625 / 50