bzoj 1391: [Ceoi2008]order 最大权闭合子图

题意

给任务和机器，机器可以租可以买，然后问获利

分析

首先想到把机器拆点租的和买的
其实不用，任务连到机器租的价格就好了
想想就好？流完代表租比较好，不然的话买比较好
要加个当前弧优化

代码

#include <bits/stdc++.h>

#define bin(i) (1<<(i))
#define pb push_back

using namespace std;

typedef long long ll;

const int inf = 1e9;
const int N = 2405;
const double eps = 1e-10;

inline int read()
{
  int p=0; int f=1; char ch=getchar();
  while(ch<'0' || ch>'9'){if(ch=='-') f=-1; ch=getchar();}
  while(ch>='0' && ch<='9'){p=p*10+ch-'0'; ch=getchar();}
  return p*f;
}

struct node
{
  int x,y,c,next;
}edge[N*1200]; int len,first[N];
void ins(int x,int y,int c)
{
  len++; edge[len].x=x; edge[len].y=y; edge[len].c=c; edge[len].next=first[x]; first[x]=len;
  len++; edge[len].x=y; edge[len].y=x; edge[len].c=0; edge[len].next=first[y]; first[y]=len;
}
int dep[N],cur[N]; queue<int>q; int s,d;
bool bfs()
{
  while(!q.empty()) q.pop(); q.push(s);
  for(int i=0;i<=d;i++) dep[i] = 0; dep[s] = 1;
  while(!q.empty())
  {
    int x=q.front(); q.pop();
    for(int k=first[x];k;k=edge[k].next)
    {
      int y=edge[k].y;
      if(dep[y] == 0 && edge[k].c)
      {
        dep[y] = dep[x]+1; q.push(y);
        if(y==d) return 1;
      }
    }
  }
  return 0;
}

int dfs(int x,int flow)
{
  if(x==d || flow ==0 ) return flow;
  int delta=0;
  for(int &k=cur[x];k;k=edge[k].next)
  {
    int y = edge[k].y;
    if(dep[y] == dep[x] + 1 && edge[k].c && flow > delta)
    {
      int minf = dfs(y,min(flow-delta,edge[k].c));
      edge[k].c-=minf; edge[k^1].c+=minf;
      delta += minf;
      if(delta == flow) break;
    }
  }
  if(delta == 0) dep[x] = 0;
  return delta;
}

struct node1
{
  int x,c;
  node1(){}
  node1(int _x,int _c){x=_x; c=_c;}
}a[N]; int val[N];

int main()
{

  len = 1;
  int n = read(); int m = read();

  int sum = 0;for(int i=1;i<=n;i++)
  {
    val[i] = read(); sum+=val[i]; ins(s,i,val[i]);
    int k = read();
    while(k--)
    {
      int x = read(); int c = read();
      ins(i,n+x,c);
    }
  }

  d = n+m+1; s = 0; //n个任务，m个机器

  for(int i=1;i<=m;i++) ins(n+i,d,read());

  int delta = 0;
  while(bfs())
  {
    for(int i=0;i<=d;i++) cur[i] = first[i];
    delta+=dfs(s,inf);
  }

  return printf("%d\n",sum-delta),0;
}