hlg1481 Attack of the Giant n-pus【二分+二分图】

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cmath>
  5 #include <vector>
  6 using namespace std;
  7 
  8 const int maxn = 101;
  9 
 10 int n, p;
 11 
 12 struct Edge
 13 {
 14     int to,next;
 15 }e[10002];
 16 int head[maxn];
 17 int tot;
 18 void add(int s,int u)
 19 {
 20     e[tot].to = u;
 21     e[tot].next = head[s];
 22     head[s] = tot++;
 23 }
 24 
 25 double xi[maxn], yi[maxn], vi[maxn];
 26 double xj[maxn], yj[maxn];
 27 double dist[maxn][maxn];
 28 
 29 int vis[maxn], Link[maxn];
 30 
 31 bool Find(int u) {
 32     for(int i = head[u]; i; i = e[i].next) {
 33         int v = e[i].to;
 34         if(!vis[v]) {
 35             vis[v] = 1;
 36             if(Link[v] == -1 || Find(Link[v]) ) {
 37                 Link[v] = u;
 38                 return true;
 39             }
 40         }
 41     }
 42     return false;
 43 }
 44 
 45 bool Match() {
 46     memset(Link, -1, sizeof(Link));
 47     for(int i = 1; i <= n; i++) {
 48         memset(vis, 0, sizeof(vis));
 49         if(!Find(i) ) return false;
 50     }
 51     return true;
 52 }
 53 
 54 double Dist(double x1, double y1, double x2, double y2) {
 55     double xx = x1 - x2;
 56     double yy = y1 - y2;
 57     return sqrt(xx * xx + yy * yy );
 58 }
 59 
 60 bool check(double mid) {
 61     tot = 1; memset(head, 0, sizeof(head));
 62     for(int i = 1; i <= n; i++) {
 63         for(int j = 1; j <= p; j ++) {
 64             if(dist[i][j] < mid) {
 65                 add(i, j);
 66             }
 67         }
 68     }
 69     if(Match()) {
 70         return true;
 71     }
 72     return false;
 73 }
 74 
 75 const double wucha = 0.0000000001;
 76 
 77 int main() {
 78     double xc, yc, vc;
 79     double xh, yh;
 80     int t;
 81     //freopen("test.txt","r",stdin);
 82     scanf("%d",&t);
 83     while(t--) {
 84         scanf("%d %d",&n, &p);
 85         scanf("%lf %lf %lf", &xc, &yc, &vc);
 86         for(int i = 1;  i <= p; i++) {
 87             scanf("%lf %lf %lf", &xi[i], &yi[i], &vi[i]);
 88         }
 89         scanf("%lf %lf", &xh, &yh);
 90         for(int i = 1; i <= n; i++) {
 91             scanf("%lf %lf", &xj[i], &yj[i]);
 92         }
 93         double low = 0, high = 0;
 94         for(int i = 1;i <= n; i++) {
 95             for(int j = 1; j <= p; j++) {
 96                 dist[i][j] = Dist(xj[i], yj[i], xi[j], yi[j]) * 1.0 / vi[j];
 97                 if(dist[i][j] > high) high = dist[i][j];
 98             }
 99         }
100         while(low < high) {
101             double mid = (low + high) * 0.5;
102             if(!check(mid)) {
103                 low = mid + wucha;
104             } else {
105                 high = mid - wucha;
106             }
107         }
108         double ans = high + wucha;
109         ans += (Dist(xc, yc, xh, yh) / vc);
110         printf("%.9lf\n", ans);
111     }
112     return 0;
113 }