HDU 2389 Rain on your Parade(二分图最大匹配--Hopcroft-Karp算法)

#include <bits/stdc++.h>
#define maxn 3010
#define inf 0x3f3f3f3f
using namespace std;
struct Node{
	int to,next;
}Edge[maxn*maxn];
struct node{
	double x,y,v;
}a[maxn];
int head[maxn],num;
int lx[maxn],ly[maxn],dx[maxn],dy[maxn];
bool vis[maxn];
int T,n,m,t,dis;

void init(){
	memset(lx,-1,sizeof(lx));
	memset(ly,-1,sizeof(ly));
	memset(head,-1,sizeof(head));
	num = 0;
}

void add(int u,int v){
	Edge[num].to = v;
	Edge[num].next = head[u];
	head[u] = num ++;
}

double dist(double x, double y, double xx, double yy){
	return sqrt((x - xx) * (x - xx) + (y - yy) * (y - yy));
}

bool Search(){
	queue<int> q;
	dis = inf;
	memset(dx,-1,sizeof(dx));
	memset(dy,-1,sizeof(dy));
	for(int i=0;i<n;i++){
		if(lx[i] == -1){
			q.push(i);
			dx[i] = 0;
		}
	}
	while(!q.empty()){
		int u = q.front();
		q.pop();
		if(dx[u] > dis) break;
		for(int i=head[u];i!=-1;i=Edge[i].next){
			int v = Edge[i].to;
			if(dy[v] == -1){
				dy[v] = dx[u] + 1;
				if(ly[v] == -1) dis = dy[v];
				else{
					dx[ly[v]] = dy[v] + 1;
					q.push(ly[v]);
				}
			}
		}
	}
	return dis != inf;
}

bool dfs(int u){
	for(int i=head[u];i!=-1;i=Edge[i].next){
		int v = Edge[i].to;
		if(!vis[v] && dy[v] == dx[u] + 1){
			vis[v] = true;
			if(ly[v] != -1 && dy[v] == dis) continue;
			if(ly[v] == -1 || dfs(ly[v])){
				ly[v] = u;
				lx[u] = v;
				return true;
			}
		}
	}
	return false;
}

int Hopcroft_Karp(){
	int sum = 0;
	while( Search() ){
		memset(vis,false,sizeof(vis));
		for(int i=0;i<n;i++){
			if(lx[i] == -1 && dfs(i)) sum ++;
		}
	}
	return sum;
}

int main()
{
	int Case = 1;
	scanf("%d",&T);
	while(T--){
		init();
		scanf("%d%d",&t,&n);
		for(int i=0;i<n;i++){
			scanf("%lf%lf%lf",&a[i].x,&a[i].y,&a[i].v);
		}
		scanf("%d",&m);
		for(int i=0;i<m;i++){
			double xx, yy;
			scanf("%lf%lf",&xx,&yy);
			for(int j=0;j<n;j++){
				double zz = dist(xx, yy, a[j].x, a[j].y);
				if(a[j].v * t >= zz){
					add(j ,i);
				}
			}
		}
		int ans = Hopcroft_Karp();
		printf("Scenario #%d:\n%d\n\n",Case ++, ans);
	}
	return 0;
}