算法模板——sap网络最大流 3（递归+邻接表）

 1 type
 2     point=^node;
 3     node=record
 4                g,w:longint;
 5                anti,next:point;
 6     end;
 7 var
 8    i,j,k,l,m,n,ans,s,t:longint;
 9    a:array[0..10000] of point;
10    d,dv:array[0..10000] of longint;
11 function min(x,y:longint):longint;inline;
12          begin
13               if x<y then min:=x else min:=y;
14          end;
15 procedure add(x,y,z:longint);inline;
16           var p:point;
17           begin
18                new(p);p^.g:=y;p^.w:=z;p^.next:=a[x];a[x]:=p;
19                new(p);p^.g:=x;p^.w:=0;p^.next:=a[y];a[y]:=p;
20                a[y]^.anti:=a[x];a[x]^.anti:=a[y];
21           end;
22 function dfs(x,flow:longint):longint;inline;
23          var i,j,k,l:longint;p:point;
24          begin
25               if x=t then exit(flow);
26               dfs:=0;p:=a[x];
27               while p<>nil do
28                     begin
29                          if (p^.w>0) and (d[x]=(d[p^.g]+1)) then
30                             begin
31                                  k:=dfs(p^.g,min(flow-dfs,p^.w));
32                                  dec(p^.w,k);
33                                  inc(p^.anti^.w,k);
34                                  inc(dfs,k);
35                                  if dfs=flow then exit;
36                             end;
37                          p:=p^.next;
38                     end;
39               if d[s]=n then exit;
40               dec(dv[d[x]]);
41               if dv[d[x]]=0 then d[s]:=n;
42               inc(d[x]);inc(dv[d[x]]);
43          end;
44 begin
45      readln(n,m,s,t);
46      for i:=1 to n do a[i]:=nil;
47      for i:=1 to m do
48          begin
49               readln(j,k,l);
50               add(j,k,l);
51          end;
52      fillchar(d,sizeof(d),0);
53      fillchar(dv,sizeof(dv),0);
54      dv[0]:=n;ans:=0;
55      while d[s]<n do inc(ans,dfs(s,maxlongint));
56      writeln(ans);
57 end.