贪心策略：就是s1+s2>s2+s1这个贪心策略非常容易发现。

#include
     
      #include
      
       #include
       
        using namespace std;const int maxn = 55;bool cmp(string s1, string s2){    return s1 + s2 > s2 + s1;}string a[maxn];int n;int main(){    while (cin >> n){        if (!n)break;        for (int i = 0; i < n; ++i)            cin >> a[i];        sort(a, a + n, cmp);        for (int i = 0; i < n; ++i)            cout << a[i];        cout << endl;    }}