Any hints for this problem?

Thinking of kittens and doors rather than Dodecahedrons helped me to find O(N) solution :)

#include <iostream>
#include <cstdlib>
#include <vector>
using namespace std;
int main()
{
    int n,m,al;
    int  aga=1,t=0;
    vector<int> algo;
    cin>>n>>m;
    int lol;
    for(int i=0;i<m;i++)
    {
        cin>>al;
    algo.push_back(al);
}
    for(int j=n;j>=1;j--)
    {
        lol=rand()%n+1;
        for(vector<int>::iterator it=algo.begin();it!=algo.end();it++)
        {
            if(*it==lol)
            {
             aga=0; break;
            }
            else
            {
        int dir=rand()%2;
        if(dir==0)
        {
            if(lol!=0) --lol;
            else ++lol;
    }
        else
        {
            if(lol!=n) ++lol;
            else --lol;
        }
    }
    }
      if(aga==1)
   {
       cout<<"NO"<<endl; t=1; break;
    }
   aga=1;
    }
      if(t==0)
        cout<<"YES"<<endl;
    }

what's the mistake?

Interestingly enough the problem can be solved with simple simulation. Just simulate the process, choosing random directions and random initial positions while you are within the time limit and you will get accepted.
I really doubt this is the correct solution, so I was wondering what is the real one?

We got CE for some reason while our compilers manage to run it.