二分图最大匹配(匈牙利算法) UVA 10080 Gopher II

题目传送门

 /*
     匈牙利算法：这题比UVA_670简单，注意是要被吃的鼠的最少个数，套模板
 */
 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <cmath>
 #include <vector>
 using namespace std;

 const int MAXN = 1e2 + ;
 const int INF = 0x3f3f3f3f;
 struct P
 {
     double x, y;
 }a[MAXN], b[MAXN];
 bool vis[MAXN];
 int lk[MAXN];
 vector<int> G[MAXN];

 double get_dis(double x1, double y1, double x2, double y2)
 {
     return sqrt ((x1-x2) * (x1-x2) + (y1-y2) * (y1-y2));
 }

 bool DFS(int u)
 {
     for (int i=; i<G[u].size (); ++i)
     {
         int v = G[u][i];
         if (!vis[v])
         {
             vis[v] = true;
             if (lk[v] == - || DFS (lk[v]))
             {
                 lk[v] = u;    return true;
             }
         }
     }

     return false;
 }

 int hungary(int n)
 {
     int res = ;    memset (lk, -, sizeof (lk));
     for (int i=; i<=n; ++i)
     {
         memset (vis, false, sizeof (vis));
         if (DFS (i))    res++;
     }

     return res;
 }

 int main(void)        //UVA 10080 Gopher II
 {
 //    freopen ("UVA_10080.in", "r", stdin);

     int n, m, s, v;
     while (scanf ("%d%d%d%d", &n, &m, &s, &v) == )
     {
         for (int i=; i<=n; ++i)    scanf ("%lf%lf", &a[i].x, &a[i].y);
         for (int i=; i<=m; ++i)    scanf ("%lf%lf", &b[i].x, &b[i].y);
         for (int i=; i<=n; ++i)    G[i].clear ();
         for (int i=; i<=n; ++i)
         {
             for (int j=; j<=m; ++j)
             {
                 if (get_dis (a[i].x, a[i].y, b[j].x, b[j].y) <= s * v)    G[i].push_back (j);
             }
         }

         printf ("%d\n", n - hungary (n));
     }

     return ;
 }