Party Games UVA

题目：题目链接

思路：排序后处理到第一个不同的字符，贪心一下就可以了

AC代码：

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

#define FRER() freopen("in.txt", "r", stdin)
#define FREW() freopen("out.txt", "w", stdout)

#define INF 0x3f3f3f3f

using namespace std;

int main()
{
    //FRER();
    //FREW();
    vector<string> vec;
    string str, ptr;
    int n;
    while(cin >> n && n) {
        vec.clear();
        for(int i = 0; i < n; ++i) {
            cin >> str;
            vec.push_back(str);
        }
        sort(vec.begin(), vec.end());
        int b = n / 2, a = b - 1;
        str = vec[a];
        ptr = vec[b];
        int len = min(str.length(), ptr.length());
        bool ok = true;
        string s = "", tmp;
        for(int i = 0; i < len; ++i) {
            if(str[i] == ptr[i])
                s += str[i];
            else {
                tmp = s + (char)(str[i] + 1);
                if(tmp == ptr) {
                    s += str[i++];
                    while(i < str.length() - 1 && str[i] == 'Z')
                        s += str[i++];
                    if(i < str.length() - 1)
                        s += (char)(str[i] + 1);
                    else
                        s = str;
                }
                else {
                    if(tmp.length() == str.length())
                        s = str;
                    else
                        s = tmp;
                }
                break;
            }
        }
        cout << s << endl;
    }
    return 0;
}