算法模板——sap网络最大流 3（递归+邻接矩阵）

 1 var
 2    s,t,i,j,k,l,m,n,ans:longint;
 3    a:array[0..1000,0..1000] of longint;
 4    d,dv:array[0..10000] of longint;
 5 function min(x,y:longint):longint;inline;
 6          begin
 7               if x<y then min:=x else min:=y;
 8          end;
 9 function dfs(x,flow:longint):longint;inline;
10          var i,j,k,l:longint;
11          begin
12               if x=t then exit(flow);
13               dfs:=0;
14               for i:=1 to n do
15                   if (a[x,i]>0) and (d[x]=(d[i]+1)) then
16                      begin
17                           k:=dfs(i,min(flow-dfs,a[x,i]));
18                           dec(a[x,i],k);
19                           inc(a[i,x],k);
20                           inc(dfs,k);
21                           if dfs=flow then exit;
22                      end;
23               if d[s]=n then exit;
24               dec(dv[d[x]]);
25               if dv[d[x]]=0 then d[s]:=n;
26               inc(d[x]);
27               inc(dv[d[x]]);
28          end;
29 begin
30      readln(n,m,s,t);
31      fillchar(a,sizeof(a),0);
32      for i:=1 to m do
33          begin
34               readln(j,k,l);
35               inc(a[j,k],l);
36          end;
37      fillchar(d,sizeof(d),0);
38      fillchar(dv,sizeof(dv),0);
39      dv[0]:=n;ans:=0;
40      while d[s]<n do inc(ans,dfs(s,maxlongint));
41      writeln(ans);
42 end.