Urinal problem Samsung

/*Men's restroom problem : It is a well-researched fact that men in a restroom generally prefer to maximize their distance from already occupied stalls, by occupying the middle of the longest sequence of unoccupied places. For detailed version, check the following link.
*/

#include <iostream>
using namespace std;

struct pos{
    int first,second;
};

int main() {
    int t=1;
    while(t--){
        int n;
        cin>>n;

        int vis[n+2]={};
        vis[0]=vis[n+1]=true;

        pos p;

        for(int fill=0; fill<n; fill++){
            int start=0; int end=1;

            p={-1,-1};

            while(end<=n){
                while(vis[end]==false) end++;

                if(p.first==-1)
                    p={start,end};
                else if( end -start >= p.second - p.first )
                    p={start,end};

                    start=end;
                    end++;
            }

            vis[(p.first + p.second)/2] = true;
            for(int i = 1; i <= n; i++) (vis[i]==true)?cout<<"X":cout<<"_";
            cout<<endl;
        }
    }
    return 0;
}