36A - Extra-terrestrial Intelligence - CodeForces Solution

#include <bits/stdc++.h>
#define ll long long
#define str string
#define ld long double
#define run_vasya_run ios_base::sync_with_stdio(0) , cin.tie(0) ,cout.tie(0)
#define ull unsigned long long
#define open freopen ("input.txt", "r", stdin);
#define close freopen("output.txt", "w", stdout);
using namespace std;
const ll MOD = 998244353;
ll _ , n , pred , mx , mn;
str s;
int main()
{
    run_vasya_run;
    open;
    close;
    int _;
    _ = 1;
    while(_ --)
    {
        cin >> n >> s;
        pred = -1;
        mx = -1e9;
        mn = 1e9;
        for(int i = 0; i < n; i ++)
        {
            if(s[i] == '1')
            {
                if(pred == -1)
                {
                    pred = i;
                    continue;
                }
                mx = max(mx, i - pred);
                mn = min(mn, i - pred);
                pred = i;
            }
        }
        if(mx == mn)
        {
            cout << "YES";
        }
        else
        {
            cout << "NO";
        }
    }

}