Bzoj 1015 [jsoi2008]starwar

题目大意：求删去图上一些点后，剩下的连通块有多少个。

解：自己终于开始有想法了，就是离线算法，把询问记录，全部删去后在反过来加上去，用并查集维护分量的根，囧死人的是不知道为什么用dfs求连通分量会wa，用并查集就ac了，而且运行时间真的有点慢了..对拍下看看哪里错了..

const
        inf='1.txt';
        maxm=211111;
        maxn=maxm << 1;
type
        type_edge=record
          dest, next, op: longint;
        end;
var
        edge: array[0..maxm*2]of type_edge;
        iq, visit: array[0..maxn]of boolean;
        stack, ans, vect, fa, ask: array[0..maxn]of longint;
        l, r: array[0..maxm]of longint;
        stacktot, ltk, n, m, q, anstot, tot: longint;
procedure add(x, y: longint);
begin
  inc(tot);
  with edge[tot] do begin
    dest := y;
    next := vect[x];
    vect[x] := tot;
    op := tot + 1;
  end;
  inc(tot);
  with edge[tot] do begin
    dest := x;
    next := vect[y];
    vect[y] := tot;
    op := tot - 1;
  end;
end;

procedure search(x, father: longint);
var
        u, i: longint;
begin
  inc(stacktot); stack[stacktot] := x; iq[x] := true;
  repeat
    u := stack[stacktot]; dec(stacktot);
    visit[u] := true;
    i := vect[u];
    while i<>0 do
      with edge[i] do begin
        if (not visit[dest])and(not iq[dest]) then begin
          inc(stacktot); stack[stacktot] := dest;
        end;
        i := next;
      end;
  until stacktot=0;
end;

function find(x: longint): longint;
begin
  if fa[x]=x then exit(x);
  fa[x] := find(fa[x]);
  exit(fa[x]);
end;

procedure init;
var
        i, x, y: longint;
begin
  anstot := 0; tot := 0; ltk := 0;
  fillchar(vect, sizeof(vect), 0);
  readln(n, m);
  dec(n);
  for i := 1 to m do begin
    readln(x, y);
    add(x, y);
    l[i] := x; r[i] := y;
  end;

  fillchar(visit, sizeof(visit), 0);
  fillchar(iq, sizeof(iq), 0);
  for i := 0 to n do fa[i] := i;
  readln(q);
  for i := 1 to q do readln(ask[i]);
  for i := 1 to q do visit[ask[i]] := true;
  for i := 0 to n do
    if not visit[i] then begin
      inc(ltk);
      stacktot := 0;
      search(i, i);
    end;
  fillchar(visit, sizeof(visit), 0);
  for i := 1 to q do visit[ask[i]] := true;{
  ltk := n+1 - q;
  for i := 1 to m do
    if (not(visit[l[i]]))and(not(visit[r[i]])) then begin
      x := find(l[i]); y := find(r[i]);
      if x<>y then begin
        dec(ltk);
        fa[y] := fa[x];
      end;
    end; }
end;


procedure push(x: longint);
var
        a, b, i: longint;
begin
  visit[x] := false; a := fa[x];
  i := vect[x];
  while i<>0 do
    with edge[i] do begin
      if (not visit[dest])and(dest<>x) then begin
        a := find(dest);
        i := next; break;
      end;
      i := next;
    end;
  if a = fa[x] then inc(ltk);
  fa[x] := a;
  while i<>0 do
    with edge[i] do begin
      if (not visit[dest])and(dest<>x) then begin
        b := find(dest);
        if a<>b then begin
          dec(ltk);
          fa[b] := fa[a];
        end;
      end;
      i := next;
    end;
end;

procedure main;
begin
  while (q>0) do begin
    inc(anstot); ans[anstot] := ltk;
    push(ask[q]);
    dec(q);
  end;
  inc(anstot); ans[anstot] := ltk;
end;

procedure print;
var
        i: longint;
begin
  for i :=anstot downto 1 do writeln(ans[i]);
end;

begin
  assign(input,inf); reset(input);
  init;
  main;
  print;
end.