pat 1038 Recover the Smallest Number (30分)

#include<iostream>
#include<cstdio>
#include<map>
#include<set>
#include<string>
#include<algorithm>
#include<vector>

using namespace std;

vector<string> vec;

bool cmp(string a, string b)
{
    return a + b < b + a;
}

int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        string t; cin >> t;
        vec.push_back(t);
    }
    sort(vec.begin(), vec.end(), cmp);
    string ans = "";
    for (int i = 0; i < n; i++)
    {
        ans += vec[i];
    }
//    cout << ans << endl;
    int i = 0;
    while (ans[i] == '0') i++;
    
    
    int len = ans.size();
    if (i >= len) {
        cout << 0 << endl;
        return 0;
    }
    for (; i < len; i++)
    {
        cout <<ans[i];
    }
    cout <<endl;
}