### 第8届浙江省程序设计竞赛点评beta » ZOJ3492

```#include <set>
#include <cctype>
#include <cstdio>
#include <string>
#include <cassert>
#include <algorithm>

using namespace std;

int main() {
int re, n;
char str;
string a;
set<string> s;

scanf("%d", &re);
for (int ri = 1; ri <= re; ++ri) {
assert(scanf("%d", &n) == 1);
assert(n % 2 == 0 && 2 <= n && n <= 100);
s.clear();
for (int i = 0; i <= n; ++i) {
assert(scanf("%s", str) == 1);
a[i] = str;
assert(a[i].length() <= 20);
for (int j = 0; j < (int)a[i].length(); ++j) {
assert(isalnum(a[i][j]));
}
if (i > 0) {
s.insert(a[i]);
}
}
int k = find(a + 1, a + 1 + n, a) - a;
assert(1 <= k && k <= n && (int)s.size() == n);
puts(a[(k - 1 + n / 2) % n + 1].c_str());
}
assert(scanf("%d", &n) == EOF);

return 0;
}

//Run ID 	Submit Time 	Judge Status 	Problem ID 	Language 	Run Time(ms) 	Run Memory(KB) 	User Name 	Admin
//471 	2011-04-15 01:46:59 	Accepted 	F 	C++ 	30 	180 	watashi 	Source
```
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