SDOI2008Cave 洞穴勘测

 1 var i,n,m,x,y:longint;
 2     ch,cha:char;
 3     fa:array[0..210000] of longint;
 4 function find(x:longint):longint;
 5  begin
 6    while x<>fa[x] do x:=fa[x];
 7    exit(x);
 8  end;
 9 procedure make(x:longint);
10  var y,tmp:longint;
11  begin
12  y:=fa[x];fa[x]:=x;
13  while y<>x do
14   begin
15   tmp:=fa[y];fa[y]:=x;
16   x:=y;y:=tmp;
17   end;
18  end;
19 procedure connect(x,y:longint);
20  begin
21  make(x);make(y);
22  fa[x]:=y;
23  end;
24 procedure destroy(x,y:longint);
25  begin
26  make(x);
27  fa[y]:=y;
28  end;
29 procedure query(x,y:longint);
30  begin
31  if find(x)<>find(y) then writeln(‘No‘) else writeln(‘Yes‘);
32  end;
33 procedure main;
34  begin
35    readln(n,m);
36    for i:=1 to n do fa[i]:=i;
37    for i:=1 to m do
38     begin
39      read(ch);cha:=‘a‘;while cha<>‘ ‘ do read(cha);readln(x,y);
40      if ch=‘C‘ then connect(x,y)
41      else if ch=‘D‘ then destroy(x,y)
42      else query(x,y);
43     end;
44  end;
45 
46 begin
47  main;
48 end.