poj 2536 二分图 最大匹配

题意：老鹰抓地鼠，跑不到洞里的就要被吃掉，求合理安排最少被吃掉

解法：左集合是地鼠，右集合是洞，在规定的时间可以到达洞里的进行连线。

/*----------------------------------   Love is more than a word.   It says so much.   When I see these four letters,   I almost feel your touch.   This is only happened since   I fell in love with you.   Why this word does this,   I haven't got a clue.                   To My Goddess                          CY----------------------------------*/#include<iostream>#include<cstring>#include<algorithm>#include<cstdlib>#include<vector>#include<cmath>#include<stdlib.h>#include<iomanip>#include<list>#include<deque>#include<map>#include <stdio.h>#include <queue>#define maxn 500+5#define ull unsigned long long #define ll long long#define reP(i,n) for(i=1;i<=n;i++) #define REP(i,a,b) for(i=a;i<=b;i++)  #define rep(i,n) for(i=0;i<n;i++)#define cle(a) memset(a,0,sizeof(a)) #define clehead(a) rep(i,maxn)a[i]=-1/*  The time of story :  **  while(1)    {         once upon a time,         there was a mountain,         on top of which there was a temple,         in which there was an old monk and a little monk.         Old monk was telling stories inside the temple.         What was he talking about?  **  }   ÎûÎû   (*^__^*)*/#define sci(a) scanf("%d",&a) #define scd(a) scanf("%lf",&a)  #define pri(a) printf("%d",a)   #define prie(a) printf("%d\n",a)    #define prd(a)  printf("%lf",a)     #define prde(a) printf("%lf\n",a)      #define pre printf("\n")#define LL(x) x<<1 #define RR(x) x<<|1#define pb push_back#define mod 90001#define PI 3.141592657const ull INF = 1LL << 61;const int inf =   int(1e5)+10;const double eps=1e-5;using namespace std;struct node{   double x,y;};node start[maxn];node end[maxn];bool cmp(int a,int b){    return a>b;}bool bmap[maxn][maxn];bool bmark[10000];int nx,ny;int cx[10000];int cy[10000];int dir[4][2]={0,-1,-1,0,1,0,0,1};int findpath(int u){    int i,j,k;    rep(i,ny){        if(bmap[u][i]&&!bmark[i]){            bmark[i]=1;            if(cy[i]==-1||findpath(cy[i]))            {                cy[i]=u;                cx[u]=i;                return 1;            }        }    }    return 0;}int maxmatch(){    int i,j,k;    int res(0);    rep(i,nx)cx[i]=-1;    rep(j,ny)cy[j]=-1;    rep(i,nx){       if(cx[i]==-1){         rep(j,ny)bmark[j]=0;         res+=findpath(i);       }    }    return res;}double len;bool getbool(node a,node b){    double temp=(a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);    return temp<=len*len;}int main(){    //freopen("in.txt","r",stdin);    //freopen("out.txt","w",stdout);    int i,j,k;    while(cin>>nx>>ny)    {        double s,v;        cin>>s>>v;        len=s*v;        rep(i,nx)        {            cin>>start[i].x>>start[i].y;        }        rep(i,ny)        {            cin>>end[i].x>>end[i].y;        }        cle(bmap);        rep(i,nx)        {            rep(j,ny)            {                if(getbool(start[i],end[j]))                {                   // cout<<i<<":"<<j<<endl;                    bmap[i][j]=true;                }            }        }        cout<<nx-maxmatch()<<endl;    }    return 0;}