zkw费用流+当前弧优化

zkw费用流+当前弧优化

 var
   o,v:array[..] of boolean;
   f,s,d,dis:array[..] of longint;
   next,p,c,w:array[-..] 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:=;
   o[i]:=true; v[i]:=true;
   while k<> do
   begin
     l:=dis[i]+w[k]-dis[j]; min:=flow;
     if c[k]<min then min:=c[k];
     if(min>)and(l<f[j])then f[j]:=l;
     if(min>)and(l=)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= 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),);
     inc(flow,dfs(ss, shl ));
     imp:= shl ;
     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= shl ;
   writeln(ans);
 end.

PASCAL

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

C++