最小费用流

zkw费用流+当前弧优化

var
  o,v:array[0..1600] of boolean;
  f,s,d,dis:array[0..1600] of longint;
  next,p,c,w:array[-100000..100000] of longint;
  i,j,k,l,y,t,ss,tt,n,ans,imp,flow:longint;
procedure link(i,j,k,l:longint);
begin
  inc(t);
  next[t]:=d[i]; d[i]:=t; p[t]:=j; c[t]:=k; w[t]:=l;
  next[-t]:=d[j]; d[j]:=-t; p[-t]:=i; w[-t]:=-l;
end;
function dfs(i,flow:longint):longint;
var j,k,l,min:longint;
begin
  if i=tt then
  begin
    inc(ans,dis[i]*flow); exit(flow);
  end;
  k:=s[i]; j:=p[k]; dfs:=0;
  o[i]:=true; v[i]:=true;
  while k<>0 do
  begin
    l:=dis[i]+w[k]-dis[j]; min:=flow;
    if c[k]<min then min:=c[k];
    if(min>0)and(l<f[j])then f[j]:=l;
    if(min>0)and(l=0)and(not o[j])then
    begin
      l:=dfs(j,min);
      inc(dfs,l); dec(flow,l);
      dec(c[k],l); inc(c[-k],l);
    end;
    if flow=0 then break;
    s[i]:=next[s[i]];
    k:=s[i]; j:=p[k];
  end;
  o[i]:=false;
end;
begin
  build;
  repeat
    for i:=ss to tt do s[i]:=d[i];
    fillchar(v,sizeof(v),false);
    fillchar(f,sizeof(f),1);
    inc(flow,dfs(ss,1 shl 20));
    imp:=1 shl 20;
    for i:=ss to tt do
    if(not v[i])and(f[i]<imp)then imp:=f[i];
    for i:=ss to tt do if not v[i] then inc(dis[i],imp);
  until imp=1 shl 20;
  writeln(ans);
end.

#include<bits/stdc++.h>
using namespace std;
const int INF=1000000000;
int o[1600],v[1600],f[1600],c[1600],s[1600],dis[1600];
int b[200001],p[200001],d[200001],w[200001];
int j,k,ss,tt,n,ans,imp,flow,cnt;
void link(int i,int j,int k,int l)
{
    cnt++; b[cnt]=c[i]; c[i]=cnt; p[cnt]=j; d[cnt]=k; w[cnt]=l;
    cnt++; b[cnt]=c[j]; c[j]=cnt; p[cnt]=i; d[cnt]=0; w[cnt]=-l;
}
int dfs(int x,int flow)
{
    if(x==tt){ ans+=dis[x]*flow; return flow; }
    int ans2=0; o[x]=1; v[x]=1;
    for(int i=s[x];i;i=b[i])
    {
        int j=p[i]; int l=dis[x]+w[i]-dis[j]; int mi=min(flow,d[i]);
        if((mi>0)and(l<f[j]))f[j]=l;
        if((mi>0)and(l==0)and(!o[j]))
        {
            l=dfs(j,mi);
            ans2+=l; flow-=l; d[i]-=l; d[i^1]+=l;
        }
        if(flow==0)break; s[x]=b[s[x]];
    }
    o[x]=0; return ans2;
}
int main()
{
    cnt=1; build;
    while(1)
    {
        for(int i=ss;i<=tt;i++)s[i]=c[i];
        memset(v,0,sizeof(v)); for(int i=ss;i<=tt;i++)f[i]=INF;
        flow+=dfs(ss,INF); imp=INF;
        for(int i=ss;i<=tt;i++)if((!v[i])and(f[i]<imp))imp=f[i];
        if(imp==INF)break;
        for(int i=ss;i<=tt;i++)if(!v[i])dis[i]+=imp;
    }
    printf("%d %d
",flow,ans);
}