71C - Round Table Knights - CodeForces Solution

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

#define f(i,j,k) for(long long i=j;i<k;i++)
#define cond(a) if(a)cout<<"YES"<<endl;else cout<<"NO"<<endl
#define yes cout<<"YES"<<endl
#define no cout<<"NO"<<endl
#define test int t;cin>>t;while(t--)
#define endl "\n"
#define pb push_back
#define mp make_pair
#define D(x) cerr << #x << " = " << (x) << '\n'
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
typedef long long ll;

ll gcd(ll a, ll b) {
    return b ? gcd(b, a % b) : a;
}
ll lcm(ll a, ll b)
{
  return (a*b)/gcd(a,b);
}
ll PRO(ll a,ll b,ll MOD)
{
  return ((a%MOD)*(b%MOD)%MOD);
}
ll power(ll x, ll y, ll M)
{
  if (y == 0)
    return 1;
  ll p = power(x, y / 2, M) % M;
  p = (p * p) % M;
  return (y % 2 == 0) ? p : (x * p) % M;
}
ll modInverse(ll A, ll M)
{
  ll g = gcd(A, M);
  if (g != 1)
    return -1;
  else {
    return power(A, M - 2, M);
  }
}
bool isprime(int n)
{

  for(int i=2;i*i<=n;i++)
  {
    if(n%i==0)return false;
  }
  return true;
}


ll fact(ll n)
{
  if(n==0)
    return 1;
  ll res = 1;
  for (ll i=2;i<=n;i++)
    res=1ll * res*i;
  return res;
}
ll C(ll n, ll r)
{
  ll z=1;
  f(i,0,r)
  {
    z=z*(n-i)/(i+1);
  }
  return z;
}
const int N=500500;
bool prime[N + 1];
void SieveOfEratosthenes(int n)
{
  memset(prime, true, sizeof(prime));
    for (int p=2;p*p<=n;p++){
      if (prime[p] == true) {
        for (int i = p * p; i <= n; i += p)
          prime[i] = false;
      }
    }
}

int lowbit(int x)
{
  return x&(-x);
}

void solve()
{
  int n;
  cin>>n;
  int a[n];
  f(i,0,n)cin>>a[i];
  set<int>v;
  for(int i=1;i*i<=n;i++)
  {
    if(n%i==0)
    {
      v.insert(i);
      v.insert(n/i);
    }
  }
  for(int x:v)
  {
    for(int i=0;i<x;i++)
    {
      bool check=true;
      int nb=0;
      for(int j=i;j<n;j+=x)
      {
        nb++;
        if(a[j]==0)
        {
          check=false;
          break;
        }
      }
      if(check && nb>2)
      {
        yes;
        return;
      }
    }
  }
  no;
}

int main()
{
  //test
  //{
    solve();
  //}
  return 0;
}