[HNOI2006]超级英雄Hero

这题一看就应该知道是二分图匹配……

我记得有个类似的题有一个并查集的解法，但是我找不到了……

 var i,n,m:longint;
     p:array[..] of longint;
     v:array[..] of boolean;
     a:array[..,..] of longint;
 function find(x:longint):boolean;
  var i,y:longint;
  begin
  for i:= to  do
   begin
   y:=a[x,i];
   if v[y] then continue;
   v[y]:=true;
   if (p[y]=) or (find(p[y])) then
    begin
    p[y]:=x;
    exit(true);
    end;
   end;
  exit(false);
  end;
 procedure main;
  begin
  readln(n,m);
  for i:= to m do begin readln(a[i,],a[i,]);inc(a[i,]);inc(a[i,]);end;
  for i:= to m do
   begin
   fillchar(v,sizeof(v),false);
   if not(find(i)) then begin writeln(i-);halt;end;
   end;
  writeln(m);
  end;
 begin
  main;
 end.