joyoi1935 「Poetize3」导弹防御塔

#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
#include <cmath>
using namespace std;
int n, m, tu, tv, v, xu[55], yu[55], xv[55], yv[55], hea[2705], cnt, cur[2705];
int ss, tt, lev[2705], maxFlow;
const int oo=0x3f3f3f3f;
double tim[55][55], fas[55];
const double eps=1e-9;
queue<int> d;
struct Edge{
	int too, nxt, val;
}edge[300005];
void add_edge(int fro, int too, int val){
	edge[cnt].nxt = hea[fro];
	edge[cnt].too = too;
	edge[cnt].val = val;
	hea[fro] = cnt++;
}
void addEdge(int fro, int too){
	add_edge(fro, too, 1);
	add_edge(too, fro, 0);
}
bool bfs(){
	memset(lev, 0, sizeof(lev));
	lev[ss] = 1;
	d.push(ss);
	while(!d.empty()){
		int x=d.front();
		d.pop();
		for(int i=hea[x]; i!=-1; i=edge[i].nxt){
			int t=edge[i].too;
			if(!lev[t] && edge[i].val>0){
				lev[t] = lev[x] + 1;
				d.push(t);
			}
		}
	}
	return lev[tt]!=0;
}
int dfs(int x, int lim){
	if(x==tt)	return lim;
	int addFlow=0;
	for(int &i=cur[x]; i!=-1 && addFlow<lim; i=edge[i].nxt){
		int t=edge[i].too;
		if(lev[t]==lev[x]+1 && edge[i].val>0){
			int tmp=dfs(t, min(lim-addFlow, edge[i].val));
			edge[i].val -= tmp;
			edge[i^1].val += tmp;
			addFlow += tmp;
			if(addFlow==lim)	break;
		}
	}
	return addFlow;
}
bool dinic(){
	maxFlow = 0;
	while(bfs()){
		for(int i=ss; i<=tt; i++)	cur[i] = hea[i];
		maxFlow += dfs(ss, oo);
	}
	return maxFlow==m;
}
bool chk(double lim){
	memset(hea, -1, sizeof(hea));
	cnt = 0;
	for(int i=1; i<=n; i++)
		for(int j=1; j<=m; j++){
			double tmptim=fas[j];
			for(int k=1; k<=m; k++)
				if(tmptim+tim[i][k]<=lim+eps)
					addEdge((i-1)*m+j, n*m+k);
			addEdge(ss, (i-1)*m+j);
		}
	for(int i=1; i<=m; i++)
		addEdge(m*n+i, tt);
	return dinic();
}
int main(){
	cin>>n>>m>>tu>>tv>>v;
	for(int i=1; i<=m; i++)
		scanf("%d %d", &xv[i], &yv[i]);
	for(int i=1; i<=n; i++)
		scanf("%d %d", &xu[i], &yu[i]);
	for(int i=1; i<=n; i++)
		for(int j=1; j<=m; j++)
			tim[i][j] = sqrt((xu[i]-xv[j])*(xu[i]-xv[j])+(yu[i]-yv[j])*(yu[i]-yv[j])) / v;
	double l=0.0, r=50000.0, mid;
	ss = 0; tt = n * m + m + 1;
	for(int i=1; i<=m; i++)
		fas[i] = (i-1) * (1.0*tu/60+tv) + 1.0*tu/60;
	for(int xx=1; xx<=100; xx++){
		mid = (l + r) / 2.0;
		if(chk(mid))	r = mid;
		else	l = mid;
	}	
	printf("%.6f\n", mid);
	return 0;
}