#1040 : 矩形判断 Algorithm

#1040 : 矩形判断
时间限制: 1000ms 单点时限: 1000ms 内存限制: 256MB 描述
给出平面上4条线段，判断这4条线段是否恰好围成一个面积大于0的矩形。
输入
输入第一行是一个整数T(1<=T<=100)，代表测试数据的数量。
每组数据包含4行，每行包含4个整数x1, y1, x2, y2 (0 <= x1, y1, x2, y2 <= 100000)；其中(x1, y1), (x2,y2)代表一条线段的两个端点。
输出
每组数据输出一行YES或者NO，表示输入的4条线段是否恰好围成矩形。
样例输入

3 0 0 0 1 1 0 1 1 0 1 1 1 1 0 0 0 0 1 2 3 1 0 3 2 3 2 2 3 1 0 0 1 0 1 1 0 1 0 2 0 2 0 1 1 1 1 0 1

样例输出

YES YES NO

#include #include #include using namespace std; struct Line { int x1, y1, x2, y2; }; int main() { int T; cin >> T; set> st; while (T--) { st.clear(); Line line1, line2, line3, line4; cin >> line1.x1 >> line1.y1 >> line1.x2 >> line1.y2; st.insert(make_pair(line1.x1, line1.y1)); st.insert(make_pair(line1.x2, line1.y2)); cin >> line2.x1 >> line2.y1 >> line2.x2 >> line2.y2; st.insert(make_pair(line2.x1, line2.y1)); st.insert(make_pair(line2.x2, line2.y2)); cin >> line3.x1 >> line3.y1 >> line3.x2 >> line3.y2; st.insert(make_pair(line3.x1, line3.y1)); st.insert(make_pair(line3.x2, line3.y2)); cin >> line4.x1 >> line4.y1 >> line4.x2 >> line4.y2; st.insert(make_pair(line4.x1, line4.y1)); st.insert(make_pair(line4.x2, line4.y2)); if (st.size() != 4) { cout << "NO" << endl; continue; }double slope1, slope2, slope3, slope4; slope1 = (line1.x1 == line1.x2) ? INT_MAX : (double)(line1.y2 - line1.y1) / (line1.x2 - line1.x1); slope2 = (line2.x1 == line2.x2) ? INT_MAX : (double)(line2.y2 - line2.y1) / (line2.x2 - line2.x1); slope3 = (line3.x1 == line3.x2) ? INT_MAX : (double)(line3.y2 - line3.y1) / (line3.x2 - line3.x1); slope4 = (line4.x1 == line4.x2) ? INT_MAX : (double)(line4.y2 - line4.y1) / (line4.x2 - line4.x1); if (slope1 == slope2) { if (slope3 != slope4) { cout << "NO" << endl; continue; } //垂直 if (((line1.y1 - line1.y2) * (line3.y1 - line3.y2) + (line1.x1 - line1.x2) * (line3.x1 - line3.x2)) == 0) { cout << "YES" << endl; }else { cout << "NO" << endl; } } /// else if (slope1 == slope3) { if (slope2 != slope4) { cout << "NO" << endl; continue; } //垂直 if (((line1.y1 - line1.y2) * (line2.y1 - line2.y2) + (line1.x1 - line1.x2) * (line2.x1 - line2.x2)) == 0) { cout << "YES" << endl; }else { cout << "NO" << endl; } } / else if(slope1 == slope4) { if (slope2 != slope3) { cout << "NO" << endl; continue; } //垂直 if (((line1.y1 - line1.y2) * (line3.y1 - line3.y2) + (line1.x1 - line1.x2) * (line3.x1 - line3.x2)) == 0) { cout << "YES" << endl; }else { cout << "NO" << endl; } } / else { cout << "NO" << endl; } } return 0; }

【#1040 : 矩形判断】