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\n",ans);
}
}