POJ 1611(并查集）

Program p1611;
const
maxn=30010;
maxm=500;
var
n,m,i,j,k,p1,p2,ans,f0:longint;
father:array[0..maxn] of longint;
function getfather(x:longint):longint;
begin
if father[x]=x then exit(x);
father[x]:=getfather(father[x]);
exit(father[x]);
end;
procedure union(x,y:longint);
begin
if getfather(x)<>getfather(y) then
father[father[x]]:=father[father[y]];
end;
begin
read(n,m);
while (n+m>0) do
begin
for i:=0 to n-1 do father[i]:=i;
for i:=1 to m do
begin
read(k);
if k>0 then read(p1);
if k>1 then
for j:=2 to k do
begin
read(p2);
union(p1,p2);
end;
end;
ans:=1;
f0:=getfather(0);
for i:=1 to n-1 do if getfather(i)=f0 then inc(ans);
writeln(ans);
read(n,m);
end;
end.