【NOI2015】软件包管理器

题面

https://www.luogu.org/problem/P2146

题解

#include<cstdio>
#include<iostream>
#include<vector>
#define N 100050
#define ri register int
using namespace std;
int n,m,clo=0,ans;
vector<int> son[N];
int siz[N],top[N],dfin[N],dfou[N],dep[N],fa[N];

void dfs1(int x,int d){
  siz[x]=1; dep[x]=d;
  for (ri i=son[x].size()-1;i>=0;i--) {
    dfs1(son[x][i],d+1);
    siz[x]+=siz[son[x][i]];
  }
}

void dfs2(int x,int tp) {
  int fs,ms=0;
  dfin[x]=++clo; top[x]=tp;
  if (son[x].size()) {
    for (ri i=son[x].size()-1;i>=0;i--) if (siz[son[x][i]]>ms) ms=siz[son[x][i]],fs=son[x][i];
    dfs2(fs,tp);
    for (ri i=son[x].size()-1;i>=0;i--) if (son[x][i]!=fs) dfs2(son[x][i],son[x][i]);
  }
  dfou[x]=clo;
}

int lb[4*N],rb[4*N],val[4*N],add[4*N];

void maketree(int x,int l,int r) {
  lb[x]=l; rb[x]=r; val[x]=0;
  if (l==r) return;
  int mid=(l+r)/2;
  maketree(2*x,l,mid); maketree(2*x+1,mid+1,r);
}

void pushdown(int x){
  if (add[x]==0) return;
  if (add[x]==1) {
    val[2*x]=rb[2*x]-lb[2*x]+1; add[2*x]=1;
    val[2*x+1]=rb[2*x+1]-lb[2*x+1]+1; add[2*x+1]=1;
  }
  else {
    val[2*x]=0; add[2*x]=2;
    val[2*x+1]=0; add[2*x+1]=2;
  }
  add[x]=0;
}

void count(int x,int l,int r) { // count0  0->1
  if (l<=lb[x] && rb[x]<=r) {
    ans+=(rb[x]-lb[x]+1-val[x]);
    val[x]=rb[x]-lb[x]+1;
    add[x]=1;
    return;
  }
  if (l>rb[x] || r<lb[x]) return;
  pushdown(x);
  count(2*x,l,r); count(2*x+1,l,r);
  val[x]=val[2*x]+val[2*x+1];
}

void count2(int x,int l,int r) {  //count1 1->0
  if (l<=lb[x] && rb[x]<=r) {
    ans+=val[x];
    val[x]=0;
    add[x]=2;
    return;
  }
  if (l>rb[x] || r<lb[x]) return;
  pushdown(x);
  count2(2*x,l,r); count2(2*x+1,l,r);
  val[x]=val[2*x]+val[2*x+1];
}

void ins(int x) {
  while (x) {
    count(1,dfin[x]-(dep[x]-dep[top[x]]),dfin[x]);
    x=fa[top[x]];
  }
}

void del(int x) {
  count2(1,dfin[x],dfou[x]);
}

int main(){
  scanf("%d",&n);
  int x;
  for (ri i=2;i<=n;i++) {
    scanf("%d",&x);
    x++;
    fa[i]=x;
    son[x].push_back(i);
  }
  dfs1(1,1);
  dfs2(1,0);
  maketree(1,1,n);
  int q;
  scanf("%d",&q);
  char s[10];
  for (ri i=1;i<=q;i++) {
    scanf("%s %d",s,&x);
    x++;
    ans=0;
    if (s[0]=='i') ins(x); else del(x);
    printf("%d
",ans);
  }
}