Submission #1054541

#	Time	Username	Problem	Language	Result	Execution time	Memory
1054541		bachhoangxuan	Secret Permutation (RMI19_permutation)	C++17	100 / 100	1860 ms	600 KiB

permutation

#include "permutation.h"
#include<bits/stdc++.h>
using namespace std;

void solve(int n){
    vector<int> D(n),P(n);
    iota(P.begin(),P.end(),1);
    shuffle(P.begin(),P.end(),mt19937(1));
    int S=0;
    for(int i=0;i<n;i++) S+=(D[i]=query(P)),rotate(P.begin(),P.begin()+1,P.end());
    S/=(n-1);

    for(int &x:D) x=S-x;
    vector<int> a(n),vis(n+1);
    function<void(int)> dfs = [&](int i){
        if(i>=n){
            if(abs(a[0]-a[n-1])!=D[0]) return;
            vector<int> res(n);
            for(int i=0;i<n;i++) res[P[i]-1]=a[i];
            answer(res);
            return;
        }
        for(int t:{-1,1}){
            int x=a[i-1]+t*D[i];
            if(1<=x && x<=n && !vis[x]){
                a[i]=x,vis[x]=1;
                dfs(i+1);
                vis[x]=0;
            }
        }
    };
    for(int i=1;i<=n;i++){
        a[0]=i,vis[i]=1;
        dfs(1);
        vis[i]=0;
    }
}

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