【SDOI2015】星际战争

#include<cstdio>
#include<queue>
using namespace std;

const int M = 10000;
const double inf = 1e18;
int n , m , h[505] , cur[505] , dep[505] , s , t , tot = 1;
double a[55] , b[55] , ans , Max;
struct edge{
	int to , nxt;
	double w;
}e[M + 5] , ee[M + 5];

inline double min(double x , double y) {return x < y ? x : y;};

inline void add(int x , int y , double w)
{
	e[++tot].to = y;
	e[tot].w = w;
	e[tot].nxt = h[x];
	h[x] = tot;
}

inline int bfs(int s , int t)
{
	for(register int i = s; i <= t; i++) dep[i] = 0 , cur[i] = h[i];
	queue<int> Q;
	dep[s] = 1;
	Q.push(s);
	while (!Q.empty())
	{
		int now = Q.front();
		Q.pop();
		for(register int i = h[now]; i; i = ee[i].nxt)
		{
			int v = ee[i].to;
			if (ee[i].w <= 0 || dep[v] != 0) continue;
			dep[v] = dep[now] + 1;
			Q.push(v);
		}
	}
	return dep[t];
}

inline double dfs(int x , int fa , double mi)
{
	if (x == t || mi <= 0) return mi;
	double flow = 0;
	for(register int i = cur[x]; i; i = ee[i].nxt)
	{
		cur[x] = i;
		int v = ee[i].to;
		if (v == fa || dep[x] + 1 != dep[v] || ee[i].w <= 0) continue;
		double f = dfs(v , x , min(mi , ee[i].w));
		if (f <= 0) continue;
		mi -= f , ee[i].w -= f , ee[i ^ 1].w += f , flow += f;
		if (mi <= 0) break;
	}
	return flow;
}

inline bool check(double mid)
{
	for(register int i = 1; i <= tot; i++) ee[i] = e[i];
	for(register int i = h[s]; i; i = ee[i].nxt)
		ee[i].w = b[ee[i].to] * mid;
	double res = 0;
	while (bfs(s , t)) res += dfs(s , 0 , inf);
	return res >= Max;
}

int main()
{
//	freopen("星际战争.in" , "r" , stdin);
	scanf("%d%d" , &n , &m);
	t = n + m + 5;
	for(register int i = 1; i <= n; i++)
	{
		scanf("%lf" , &a[i]);
		Max += a[i];
		add(i + m , t , a[i]);
		add(t , i + m , 0);	
	}
	for(register int i = 1; i <= m; i++) 
	{
		scanf("%lf" , &b[i]);
		add(s , i , b[i]);
		add(i , s , 0);
	}
	int x;
	for(register int i = 1; i <= m; i++)
		for(register int j = 1; j <= n; j++)
		{
			scanf("%d" , &x);
			if (x == 1) add(i , j + m , inf) , add(j + m , i , 0);
		}
	double l = 0 , r = 1e9 , mid;
	for(register int i = 1; i <= 60; i++)
	{
		mid = (l + r) * 0.5;
		if (check(mid)) r = mid , ans = mid;
		else l = mid;
	}
	printf("%.6lf" , ans);
}