614B - Gena's Code - CodeForces Solution

#include <iostream>
#include <bits/stdc++.h>
#define WINNABLE ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define PRINTVP(vp) for(auto &i:vp)cout<<i.first<<" "<<i.second<<endl;
#define PRINTV(v) for(auto &i:v)cout<<i<<" ";
#define endl '\n'
typedef long long ll;
using namespace std;

bool notBeautiful(string s) {
    int ones = 0;
    for(char c : s) {
        if((c - '0') > 1)
            return true;
        if((c - '0') == 1)
            ones++;
    }
    if(ones > 1)
        return true;
    return false;
}

int main()
{
    int n; cin >> n;
    string s, zeros, nbtfl = "1";
    if(n == 1) {
        cin >> s;
        return cout << s, 0;
    }
    for(int i = 0; i < n; i++) {
        cin >> s;
        if(s == "0")
            return cout << 0, 0;
        if(notBeautiful(s)) {
            nbtfl = s;
        }
        else {
            for(char c : s) {
                if((c - '0') == 0)
                    zeros += '0';
            }
        }
    }
    cout << nbtfl << zeros;
}