1877: [SDOI2009]晨跑 费用流

拆点费用流。。

#include<iostream>#include<cstdio>#include<cstring>#define M 405#define inf 1000000007using 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;}