poj1127 Jack Straws(线段相交+并查集)

  1 /**
  2  * code generated by JHelper
  3  * More info: https://github.com/AlexeyDmitriev/JHelper
  4  * @author xyiyy @https://github.com/xyiyy
  5  */
  6 
  7 #include <iostream>
  8 #include <fstream>
  9 
 10 //#####################
 11 //Author:fraud
 12 //Blog: http://www.cnblogs.com/fraud/
 13 //#####################
 14 //#pragma comment(linker, "/STACK:102400000,102400000")
 15 #include <iostream>
 16 #include <sstream>
 17 #include <ios>
 18 #include <iomanip>
 19 #include <functional>
 20 #include <algorithm>
 21 #include <vector>
 22 #include <string>
 23 #include <list>
 24 #include <queue>
 25 #include <deque>
 26 #include <stack>
 27 #include <set>
 28 #include <map>
 29 #include <cstdio>
 30 #include <cstdlib>
 31 #include <cmath>
 32 #include <cstring>
 33 #include <climits>
 34 #include <cctype>
 35 
 36 using namespace std;
 37 #define rep(X, N) for(int X=0;X<N;X++)
 38 #define rep2(X, L, R) for(int X=L;X<=R;X++)
 39 
 40 const int MAXN = 110;
 41 //
 42 // Created by xyiyy on 2015/8/8.
 43 //
 44 
 45 #ifndef JHELPER_EXAMPLE_PROJECT_UNIONFINDSET_HPP
 46 #define JHELPER_EXAMPLE_PROJECT_UNIONFINDSET_HPP
 47 
 48 int pa[MAXN], ra[MAXN];
 49 
 50 void init(int n) {
 51     rep(i, n + 1)pa[i] = i, ra[i] = 0;
 52 }
 53 
 54 int find(int x) {
 55     if (pa[x] != x)pa[x] = find(pa[x]);
 56     return pa[x];
 57 }
 58 
 59 int unite(int x, int y) {
 60     x = find(x);
 61     y = find(y);
 62     if (x == y)return 0;
 63     if (ra[x] < ra[y])pa[x] = y;
 64     else {
 65         pa[y] = x;
 66         if (ra[x] == ra[y])ra[x]++;
 67     }
 68     return 1;
 69 }
 70 
 71 bool same(int x, int y) {
 72     return find(x) == find(y);
 73 }
 74 
 75 #endif //JHELPER_EXAMPLE_PROJECT_UNIONFINDSET_HPP
 76 
 77 //
 78 // Created by xyiyy on 2015/8/10.
 79 //
 80 
 81 #ifndef JHELPER_EXAMPLE_PROJECT_P_HPP
 82 #define JHELPER_EXAMPLE_PROJECT_P_HPP
 83 
 84 
 85 const double EPS = 1e-9;
 86 
 87 class P {
 88 public:
 89     double x, y;
 90 
 91     P() { }
 92 
 93     P(double _x, double _y) {
 94         x = _x;
 95         y = _y;
 96     }
 97 
 98     double add(double a, double b) {
 99         if (fabs(a + b) < EPS * (fabs(a) + fabs(b)))return 0;
100         return a + b;
101     }
102 
103     P  operator+(const P &p) {
104         return P(add(x, p.x), add(y, p.y));
105     }
106 
107     P operator-(const P &p) {
108         return P(add(x, -p.x), add(y, -p.y));
109     }
110 
111     P operator*(const double &d) {
112         return P(x * d, y * d);
113     }
114 
115     P operator/(const double &d) {
116         return P(x / d, y / d);
117     }
118 
119     double det(P p) {
120         return add(x * p.y, -y * p.x);
121     }
122 
123     //线段相交判定
124     bool crsSS(P p1, P p2, P q1, P q2) {
125         if (max(p1.x, p2.x) + EPS < min(q1.x, q2.x))return false;
126         if (max(q1.x, q2.x) + EPS < min(p1.x, p2.x))return false;
127         if (max(p1.y, p2.y) + EPS < min(q1.y, q2.y))return false;
128         if (max(q1.y, q2.y) + EPS < min(p1.y, p2.y))return false;
129         /*(if((p1 - p2).det(q1 - q2) == 0){
130             return (on_seg(p1,p2,q1) || on_seg(p1,p2,q2) || on_seg(q1,q2,p1) || on_seg(q1,q2,p2));
131         }else{
132             P r = intersection(p1,p2,q1,q2);
133             return on_seg(p1,p2,r) && on_seg(q1,q2,r);
134 
135         }*/
136         return (p2 - p1).det(q1 - p1) * (p2 - p1).det(q2 - p1) <= 0
137                && (q2 - q1).det(p1 - q1) * (q2 - q1).det(p2 - q1) <= 0;
138     }
139 
140     //直线和直线的交点
141     /*P isLL(P p1,P p2,P q1,P q2){
142         double d = (q2 - q1).det(p2 - p1);
143         if(sig(d)==0)return NULL;
144         return intersection(p1,p2,q1,q2);
145     }*/
146 
147     //四点共圆判定
148     /*bool onC(P p1,P p2,P p3,P p4){
149         P c = CCenter(p1,p2,p3);
150         if(c == NULL) return false;
151         return add((c - p1).abs2(), -(c - p4).abs2()) == 0;
152     }*/
153 
154     //三点共圆的圆心
155     /*P CCenter(P p1,P p2,P p3){
156         //if(disLP(p1, p2, p3) < EPS)return NULL;//三点共线
157         P q1 = (p1 + p2) * 0.5;
158         P q2 = q1 + ((p1 - p2).rot90());
159         P s1 = (p3 + p2) * 0.5;
160         P s2 = s1 + ((p3 - p2).rot90());
161         return isLL(q1,q2,s1,s2);
162     }*/
163 
164 
165 };
166 
167 
168 #endif //JHELPER_EXAMPLE_PROJECT_P_HPP
169 
170 class poj1127 {
171 public:
172     void solve(std::istream &in, std::ostream &out) {
173         int n;
174         P *p = new P[110];
175         P *q = new P[110];
176         while (in >> n && n) {
177             init(n + 5);
178             rep2(i, 1, n) {
179                 in >> p[i].x >> p[i].y >> q[i].x >> q[i].y;
180             }
181             rep2(i, 1, n) {
182                 rep2(j, 1, n) {
183                     if (p[i].crsSS(p[i], q[i], p[j], q[j]))unite(i, j);
184                 }
185             }
186             int u, v;
187             while (in >> u >> v && (u && v)) {
188                 if (same(u, v))out << "CONNECTED" << endl;
189                 else out << "NOT CONNECTED" << endl;
190             }
191         }
192     }
193 };
194 
195 int main() {
196     std::ios::sync_with_stdio(false);
197     std::cin.tie(0);
198     poj1127 solver;
199     std::istream &in(std::cin);
200     std::ostream &out(std::cout);
201     solver.solve(in, out);
202     return 0;
203 }