Educational Codeforces Round 9 -- C - The Smallest String Concatenation

C. The Smallest String Concatenation

time limit per test

3 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

You're given a list of n strings a1, a2, ..., an. 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 ai (1 ≤ |ai| ≤ 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.

Examples

input

4
abba
abacaba
bcd
er

output

abacabaabbabcder

input

5
x
xx
xxa
xxaa
xxaaa

output

xxaaaxxaaxxaxxx

input

3
c
cb
cba

output

cbacbc

大体题意：

输入n个字符串，把这n个字符串合成一个字符串（就是字符串的拼接），使得这个字符串字典序最小！

思路：

输入字符串后，直接sort就好了！

cmp直接return a + b < b + a，始终按两个字符串相加字典序最小排序！

#include<bits/stdc++.h>
using namespace std;
const int maxn = 50000 + 10;
string s[maxn];
bool cmp(const string &a,const string &b){
    return a + b < b + a;
}
int main()
{
    int n;
    while(scanf("%d",&n) == 1){
        for (int i = 0; i < n; ++i)cin >> s[i];
        sort(s,s+n,cmp);
        for (int i = 0; i < n; ++i)cout << s[i];
        printf("\n");
    }
    return 0;
}