DINIC网络流+当前弧优化

深搜网络流+当前弧优化

 const
   inf=;
 type
   rec=record
     s,e,w,next:longint;
   end;
 var
   b,bb,d,q:array[-..] of longint;
   a:array[-..] of rec;
   n,m,i,j,k,l,st,ed,ww,top,ans,nn,dd,x:longint;
 function min(aa,bb:longint):longint;
 begin
   if aa<bb then exit(aa);exit(bb);
 end;
 procedure add(st,ed,ww:longint);
 begin
   inc(top);
   a[top].s:=st;
   a[top].e:=ed;
   a[top].w:=ww;
   a[top].next:=b[st];
   b[st]:=top;
 end;
 function addflow(p,maxflow:longint):longint;
 var
   o,u:longint;
 begin
   if(p=ed)or(maxflow=)then exit(maxflow);
   d[p]:=;
   addflow:=; u:=bb[p];
   while u> do
   begin
     if(a[u].w>)and(d[a[u].e]=)then
     begin
       o:=addflow(a[u].e,min(maxflow,a[u].w));
       if o> then
       begin
         dec(a[u].w,o); if a[u].w> then bb[p]:=u;
         inc(a[u xor ].w,o);
         dec(maxflow,o); inc(addflow,o);
         if maxflow= then break;
       end;
     end;
     u:=a[u].next;
   end;
 end;
 function network:longint;
 var i,last:longint;
 begin
   network:=; last:=;
   while true do
   begin
     for i:=st to ed do begin bb[i]:=b[i]; d[i]:=; end;
     inc(network,addflow(st,inf));
     if network=last then exit;
     last:=network;
   end;
 end;
 begin
   readln(n,m);
   top:=; build;
   writeln(network);
 end.

DINIC网络流+当前弧优化

 const
   inf=;
 type
   rec=record
     s,e,w,next:longint;
   end;
 var
   b,bb,d,q:array[-..] of longint;
   a:array[-..] of rec;
   n,m,i,j,k,l,st,ed,ww,top,ans,nn,dd,x:longint;
 function min(aa,bb:longint):longint;
 begin
   if aa<bb then exit(aa);exit(bb);
 end;
 procedure add(st,ed,ww:longint);
 begin
   inc(top);
   a[top].s:=st;
   a[top].e:=ed;
   a[top].w:=ww;
   a[top].next:=b[st];
   b[st]:=top;
 end;
 function bfs:boolean;
 var head,tail,x,u,i:longint;
   y:rec;
 begin
   for i:=st to ed do d[i]:=-;
   tail:=; head:=; d[st]:=; q[]:=st;
   while head<tail do
   begin
     inc(head); x:=q[head];
     u:=b[x];
     while u> do
     begin
       y:=a[u];
       if(d[y.e]=-)and(y.w>)then
       begin
         d[y.e]:=d[x]+;
         inc(tail); q[tail]:=y.e;
       end;
       u:=y.next;
     end;
   end;
   if d[ed]=- then exit(false);
   exit(true);
 end;
 function addflow(p,maxflow:longint):longint;
 var
   o,u:longint;
 begin
   if(p=ed)or(maxflow=)then exit(maxflow);
   addflow:=; u:=bb[p];
   while u> do
   begin
     if(d[a[u].e]=d[p]+)and(a[u].w>)then
     begin
       o:=addflow(a[u].e,min(maxflow,a[u].w));
       if o> then
       begin
         dec(a[u].w,o); if a[u].w> then bb[p]:=u;
         inc(a[u xor ].w,o);
         dec(maxflow,o); inc(addflow,o);
         if maxflow= then break;
       end;
     end;
     u:=a[u].next;
   end;
   if addflow= then d[p]:=-;
 end;
 function network:longint;
 var i:longint;
 begin
   network:=;
   while bfs do
   begin
     for i:=st to ed do bb[i]:=b[i];
     inc(network,addflow(st,inf));
   end;
 end;
 begin
   readln(n,m);
   top:=; build;
   writeln(network);
 end.

PASCAL

 #include<bits/stdc++.h>
 using namespace std;
 const int INF=;
 int n,m,ss,tt,flow,l,r,lb[];
 int c[],c2[],b[][],dis[];
 void adedg(int x,int y,int z)
 {
     m++; b[m][]=z; b[m][]=y; b[m][]=c[x]; c[x]=m;
     m++; b[m][]=; b[m][]=x; b[m][]=c[y]; c[y]=m;
 }
 bool bfs()
 {
     for(int i=ss;i<=tt;i++)dis[i]=-; dis[ss]=;
     l=; r=; lb[r]=ss;
     while(l<r)
     {
         l++; int x=lb[l];
         for(int i=c[x];i;i=b[i][])
         if((dis[b[i][]]==-)and(b[i][]>))
         { dis[b[i][]]=dis[x]+; r++; lb[r]=b[i][]; }
     }
     if(dis[tt]!=-)return ;
     return ;
 }
 int work(int x,int ma)
 {
     if((ma==)or(x==tt))return ma;
     int add=;
     while(c2[x])
     {
         int i=c2[x];
         if(dis[b[i][]]==dis[x]+)
         {
             int l=work(b[i][],min(b[i][],ma)); add+=l; ma-=l;
             b[i][]-=l; b[i^][]+=l;
             if(ma==)return add;
         }
         c2[x]=b[c2[x]][];
     }
     return add;
 }
 int main()
 {
     m=; build();
     flow=;
     while(bfs())
     {
         for(int i=ss;i<=tt;i++)c2[i]=c[i];
         flow+=work(ss,INF);
     }
     printf("%d\n",flow);
 }

C++