codeforces 632C C The Smallest String Concatenation（背包）

C - The Smallest String Concatenation

Time Limit:3000MS    Memory Limit:262144KB    64bit IO Format:%I64d & %I64u

Submit Status Practice CodeForces 632C

Description

You're given a list of n strings a₁, a₂, ..., a_n. You'd like to concatenate them together in some order such that the resulting string would be lexicographically smallest.

Given the list of strings, output the lexicographically smallest concatenation.

Input

The first line contains integer n — the number of strings (1 ≤ n ≤ 5·10⁴).

Each of the next n lines contains one string a_i (1 ≤ |a_i| ≤ 50) consisting of only lowercase English letters. The sum of string lengths will not exceed 5·10⁴.

Output

Print the only string a — the lexicographically smallest string concatenation.

Sample Input

Input

4
abba
abacaba
bcd
er

Output

abacabaabbabcder

Input

5
x
xx
xxa
xxaa
xxaaa

Output

xxaaaxxaaxxaxxx

Input

3
c
cb
cba

Output

cbacbc

这个题目竟然是用到string类，我才刚学了，凑活会用点，但是没想到cmp函数是如此的巧妙，竟然直接sort排序就ok了，而我还在想怎么在字符串后面添加字符，想歪了啊！

代码如下：

#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
string str[50005];
int cmp(string str1,string str2)
{
    return str1+str2<str2+str1;
}
int main()
{
    int n;
    cin>>n;
    for(int i=0;i<n;i++)
        cin>>str[i];
        sort(str,str+n,cmp);
        for(int i=0;i<n;i++)
            cout <<str[i];
        cout <<endl;
        return 0;
}