题意：给一个向量输出任意与它垂直的向量 ，不能出现负数。
思路：直接输出(d, a) (b, c)
代码如下：
1 /************************************************** 2 * Author : xiaohao Z 3 * Blog : http://www.cnblogs.com/shu-xiaohao/ 4 * Last modified : 2014-07-05 20:23 5 * Filename : uva_12714.cpp 6 * Description : 7 * ************************************************/ 8 9 #include <iostream> 10 #include <cstdio> 11 #include <cstring> 12 #include <cstdlib> 13 #include <cmath> 14 #include <algorithm> 15 #include <queue> 16 #include <stack> 17 #include <vector> 18 #include <set> 19 #include <map> 20 #define MP(a, b) make_pair(a, b) 21 #define PB(a) push_back(a) 22 23 using namespace std; 24 typedef long long ll; 25 typedef pair<int, int> pii; 26 typedef pair<unsigned int,unsigned int> puu; 27 typedef pair<int, double> pid; 28 typedef pair<ll, int> pli; 29 typedef pair<int, ll> pil; 30 31 const int INF = 0x3f3f3f3f; 32 const double eps = 1E-6; 33 34 int main() 35 { 36 // freopen("in.txt", "r", stdin); 37 38 ll a, b, c, d, kase = 1, T; 39 cin >> T; 40 while(T--){ 41 cin >> a >> b >> c >> d; 42 cout << "Case " << kase++ << ": "; 43 cout << d << ' ' << a << ' ' << b << ' ' << c << endl; 44 } 45 return 0; 46 }