【字符串排序，技巧！】UVa 10905 - Children’s Game

There are lots of number games for children. These games are pretty easy to play but not so easy to make. We will discuss about an interesting game here. Each player will be given N positive integer. (S)He can make a big integer by appending those integers after one another. Such as if there are 4 integers as 123, 124, 56, 90 then the following integers can be made – 1231245690, 1241235690, 5612312490, 9012312456, 9056124123 etc. In fact 24 such integers can be made. But one thing is sure that 9056124123 is the largest possible integer which can be made.

You may think that it’s very easy to find out the answer but will it be easy for a child who has just got the idea of number?

Input

Each input starts with a positive integer N (≤ 50). In next lines there are N positive integers. Input is terminated by N = 0, which should not be processed.

Output

For each input set, you have to print the largest possible integer which can be made by appending all the N integers.

Sample Input

4
123 124 56 90
5
123 124 56 90 9
5
9 9 9 9 9
0

Output for Sample Input

9056124123
99056124123
99999

 题意：使字符串组合最大；

 

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

技巧性比较强。注意遇到类似题型时运用；

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
const int maxn = 55;
string str[maxn];
bool cmp(string a, string b)
{
    return a+b > b+a;
}
int main()
{
    int n;
    while(cin >> n && 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;
}