算法模板——二分图匹配

 1 type
 2     point=^node;
 3     node=record
 4                g:longint;
 5                next:point;
 6     end;
 7 var
 8    i,j,k,l,m,n:longint;
 9    c,f:array[0..1000] of longint;
10    a:array[0..1000] of point;
11 procedure add(x,y:longint);inline;
12           var p:point;
13           begin
14                new(p);
15                p^.g:=y;
16                p^.next:=a[x];
17                a[x]:=p;
18           end;
19 function check(x:longint):boolean;inline;
20          var p:point;
21          begin
22               p:=a[x];
23               while p<>nil do
24                     begin
25                          if f[p^.g]<>i then
26                             begin
27                                  f[p^.g]:=i;
28                                  if c[p^.g]=0 then
29                                     begin
30                                          c[p^.g]:=x;
31                                          exit(true);
32                                     end
33                                  else if check(c[p^.g]) then
34                                       begin
35                                            c[p^.g]:=x;
36                                            exit(true);
37                                       end;
38                             end;
39                          p:=p^.next;
40                     end;
41               exit(false);
42          end;
43 
44 {$IFDEF WINDOWS}{$R wiki2776.rc}{$ENDIF}
45 
46 begin
47      readln(n,m);
48      for i:=1 to n do
49          begin
50               a[i]:=nil;
51               while not(eoln) do
52                     begin
53                          read(j);
54                          if j=0 then break;
55                          add(i,j);
56                     end;
57               readln;
58          end;
59      fillchar(c,sizeof(c),0);
60      fillchar(f,sizeof(f),0);l:=0;
61      for i:=1 to n do
62          if check(i) then inc(l);
63      writeln(l);
64      readln;
65 end.
66