1877: [SDOI2009]晨跑 费用流

#include<iostream>
#include<cstdio>
#include<cstring>
#define M 405
#define inf 1000000007
using namespace std;
int n,m,T,cnt=1,ans1,ans2;
int head[405],dis[405],q[405],path[405];
bool vis[405];
int list[50005],next[50005],from[50005],flow[50005],cost[50005];
inline int read()
{
int a=0,f=1; char c=getchar();
while (c<'0'||c>'9') {if (c=='-') f=-1; c=getchar();}
while (c>='0'&&c<='9') {a=a*10+c-'0'; c=getchar();}
return a*f;
}
inline void insert(int x,int y,int z,int w)
{
next[++cnt]=head[x];
head[x]=cnt;
from[cnt]=x;
list[cnt]=y;
flow[cnt]=z;
cost[cnt]=w;
}
inline bool spfa()
{
for (int i=1;i<=T;i++) dis[i]=inf;
dis[1]=0; q[1]=1; vis[1]=1;
int t=0,w=1,x;
while (t!=w)
{
t=(t+1)%M;
x=q[t];
for (int i=head[x];i;i=next[i])
if (flow[i]&&dis[list[i]]>dis[x]+cost[i])
{
dis[list[i]]=dis[x]+cost[i];
path[list[i]]=i;
if (!vis[list[i]])
{
vis[list[i]]=1;
w=(w+1)%M;
q[w]=list[i];
}
}
vis[x]=0;
}
return dis[T]!=inf;
}
inline void mcf()
{
int x=inf;
for (int i=path[T];i;i=path[from[i]]) x=min(x,flow[i]);
for (int i=path[T];i;i=path[from[i]])
ans2+=x*cost[i],flow[i]-=x,flow[i^1]+=x;
ans1+=x;
}
int main()
{
n=read(); m=read(); T=2*n;
for (int i=1;i<=m;i++)
{
int u=read(),v=read(),w=read();
insert(u+n,v,1,w); insert(v,u+n,0,-w);
}
insert(1,n+1,inf,0); insert(n+1,1,0,0);
insert(n,n+n,inf,0); insert(n+n,n,0,0);
for (int i=2;i<n;i++)
insert(i,i+n,1,0),insert(i+n,i,0,0);
while (spfa()) mcf();
cout << ans1 << " " << ans2 << endl;
return 0;
}