Submission #1054082

#	Time	Username	Problem	Language	Result	Execution time	Memory
1054082		huutuan	Secret Permutation (RMI19_permutation)	C++14	60 / 100	15 ms	596 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;
   vector<int> d2(n+1);
   sort(v.begin(), v.end(), [&](int x, int y){
      if ((x&1)!=(y&1)) return (x&1)<(y&1);
      return x<y;
   });
   for (int i=0; i<n; ++i){
      d2[v[0]]=query(v);
      rotate(v.begin(), v.begin()+1, v.end());
   }
   sum=accumulate(d2.begin(), d2.end(), 0)/(n-1);
   for (int &i:d2) i=sum-i;
   if (d1[2]+d1[3]==d2[3]){
      ans[2]=ans[1]+d1[2];
      ans[3]=ans[2]+d1[3];
   }else if (d1[2]+d2[3]==d1[3]){
      ans[1]=ans[2]+d1[2];
      ans[3]=ans[1]+d2[3];
   }else{
      ans[3]=ans[1]+d2[3];
      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])==d2[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: 9 / 15
• Subtask 2: 21 / 35
• Subtask 3: 30 / 50