976A - Minimum Binary Number - CodeForces Solution

#include<bits/stdc++.h>
#define 	ll				long long
#define 	vi				vector<int>
#define 	vll				vector<long long>
#define 	all(x)			(x).begin(),(x).end()
#define		allr(x)			(x).rbegin(),(x).rend()
#define		nl				"\n"
#define 	nayon			ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
using namespace std;

int main(){
    //int t;cin>>t; while(t--){
        int n;cin>>n;
        string s;cin>>s;
        int z=0;
        if(n==1) cout<<s<<nl;
        else{
            for(int i=0;i<s.size();++i){
                if(s[i]=='0') z++;
            }
            cout<<'1'<<string(z,'0')<<nl;
        }
    //}
}