Submission #217826

#	Time	Username	Problem	Language	Result	Execution time	Memory
217826		2fat2code	Secret Permutation (RMI19_permutation)	C++17	100 / 100	670 ms	512 KiB

permutation

#include "permutation.h"
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define all(a) (a).begin(), (a).end()
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define sz() size()
#define fr first
#define sc second
#define pi pair<int,int>
#define pii pair<pair<int,int>,int>
#define mp make_pair
//#define int long long
#define rc(s) return cout<<s,0
#define rcc(s) cout<<s,exit(0)
using namespace std;

const int mod=1e9+7;
const int modp=1999999973;
const int modulo=998244353;

int n;
bitset<257>viz;
vector<int>v,arr(257),ans(257),fin(257);
vector<int>answ;

void DFS(int curr){
    viz[ans[curr]]=1;
    if(curr==n && abs(ans[curr]-ans[1])==arr[n]){
        for(int i=1;i<=n;i++){
            fin[v[i-1]]=ans[i];
        }
        for(int i=1;i<=n;i++){
            answ.push_back(fin[i]);
        }
        answer(answ);
        exit(0);
    }
    else{
        int x1=(ans[curr] - arr[curr]);
        int x2=(ans[curr] + arr[curr]);
        if(x1>=1 && x1<=n && viz[x1]==0 && abs(x1-ans[curr])==arr[curr]){
            ans[curr+1]=(x1);
            DFS(curr+1);
        }
        if(x2>=1 && x2<=n && viz[x2]==0 && abs(x2-ans[curr])==arr[curr]){
            ans[curr+1]=(x2);
            DFS(curr+1);
        }
    }
    viz[ans[curr]]=0;
    ans[curr]=0;
}

void solve(int N){
    ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
    srand(chrono::steady_clock::now().time_since_epoch().count());
    n=N;
    for(int i=1;i<=n;i++){
        v.push_back(i);
    }
    random_shuffle(all(v));
    for(int i=1;i<=n;i++){
        rotate(v.begin(),v.begin()+1,v.end());
        arr[i] = query(v);
    }
    rotate(v.begin(),v.begin()+1,v.end());
    int sum=0;
    for(int i=1;i<=n;i++){
        sum+=arr[i];
    }
    sum/=(n-1);
    for(int i=1;i<=n;i++) arr[i]=(sum-arr[i]);
    arr[n+1]=arr[1];
    for(int i=1;i<=n;i++) arr[i]=arr[i+1];
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++) ans[j]=0;
        ans[1]=i;
        viz.reset();
        DFS(1);
    }
}

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]
   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]
   fscanf(stdin, "%d", &N);
   ~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 50 / 50