#include <bits/stdc++.h> using namespace std; //20.54 bool isbro(string s1, string s2) { /*兄弟单词:首先长度要一样,其次每个字母出现的频数要一样*/ if (s1 == s2) return false; if (s1.length() != s2.length()) return false; vector<char> v(26, 0); for (int i = 0; i < s1.length(); i++) { v[s1[i] - 'a']++; v[s2[i] - 'a']--; } for (int i = 0; i < 26; i++) { if (v[i] != 0) return false; } return true; } int main() { int n; string s; int k; while (cin >> n) { vector<string> v; vector<string> bro; while (n--) { cin >> s; v.push_back(s); } cin >> s; //然后输入一个单词x cin >> k; int pos = -1; //检查是不是兄弟单词 for (int i = 0; i < v.size(); i++) { if (isbro(v[i], s)) { bro.push_back(v[i]); } } sort(bro.begin(), bro.end()); cout << bro.size() << endl; if (k <= bro.size()) { cout << bro[k - 1]; } } } // 64 位输出请用 printf("%lld")