原题传送门
首先，对着样例手模一遍就理解题意啦
然后发现这又是一道树剖
维护一颗线段树，seg[rt].sum表示该区间内安装的软件包个数

• 安装操作，往根节点跳上去，其间所有经过的点全部状态改为安装
• 卸载操作，自己子树包括自己状态全部改为不安装

发现两中操作的答案都是delta(seg[1].sum)
细节问题需要注意啦

Code:

#include <bits/stdc++.h>
#define maxn 100010
#define ls rt << 1
#define rs rt << 1 | 1
using namespace std;
struct Edge{
	int to, next;
}edge[maxn << 1];
struct Seg{
	int l, r, sum, tag;
}seg[maxn << 2];
int head[maxn], num, d[maxn], fa[maxn], size[maxn], son[maxn], id[maxn], cnt, top[maxn], n;

inline int read(){
	int s = 0, w = 1;
	char c = getchar();
	for (; !isdigit(c); c = getchar()) if (c == '-') w = -1;
	for (; isdigit(c); c = getchar()) s = (s << 1) + (s << 3) + (c ^ 48);
	return s * w;
}

void add_edge(int x, int y){ edge[++num].to = y; edge[num].next = head[x]; head[x] = num; }

void dfs(int u){
	size[u] = 1, son[u] = -1;
	for (int i = head[u]; i; i = edge[i].next){
		int v = edge[i].to;
		if (v != fa[u]){
			fa[v] = u, d[v] = d[u] + 1;
			dfs(v);
			size[u] += size[v];
			if (son[u] == -1 || son[u] != -1 && size[son[u]] < size[v]) son[u] = v;
		}
	}
}

void dfs(int u, int x){
	id[u] = ++cnt, top[u] = x;
	if (son[u] == -1) return;
	dfs(son[u], x);
	for (int i = head[u]; i; i = edge[i].next){
		int v = edge[i].to;
		if (v != son[u] && v != fa[u]) dfs(v, v);
	}
}

void pushup(int rt){ seg[rt].sum = seg[ls].sum + seg[rs].sum; }

void pushdown(int rt){下传tag
	seg[ls].sum = (seg[ls].r - seg[ls].l + 1) * seg[rt].tag;
	seg[rs].sum = (seg[rs].r - seg[rs].l + 1) * seg[rt].tag;
	seg[ls].tag = seg[rs].tag = seg[rt].tag;
	seg[rt].tag = -1;
}

void build(int rt, int l, int r){
	seg[rt].l = l, seg[rt].r = r; seg[rt].tag = -1;
	if (l == r) return;
	int mid = (l + r) >> 1;
	build(ls, l, mid); build(rs, mid + 1, r);
}

void update(int rt, int l, int r, int k){
	if (seg[rt].l > r || seg[rt].r < l) return;
	if (seg[rt].l >= l && seg[rt].r <= r){
		seg[rt].sum = (seg[rt].r - seg[rt].l + 1) * k;//更改状态
		seg[rt].tag = k;
		return;
	}
	if (seg[rt].tag != -1) pushdown(rt);
	update(ls, l, r, k); update(rs, l, r, k);
	pushup(rt);
}

int main(){
	n = read();
	for (int i = 1; i < n; ++i){
		int x = read();
		add_edge(x + 1, i + 1); add_edge(i + 1, x + 1);
	}
	dfs(1); dfs(1, 1); 
	build(1, 1, n);
	int m = read();
	while (m--){
		char c = getchar(); for (; c != 'i' && c != 'u'; c = getchar());
		if (c == 'i'){
			int tmp = seg[1].sum, x = read(); ++x;
			while (top[x] != 1){
				update(1, id[top[x]], id[x], 1);
				x = fa[top[x]];
			} 
			update(1, id[top[x]], id[x], 1); 
			printf("%d\n", abs(tmp - seg[1].sum));
		} else{
			int tmp = seg[1].sum, x = read(); ++x;
			update(1, id[x], id[x] + size[x] - 1, 0); 
			printf("%d\n", abs(tmp - seg[1].sum));
		}
	}
	return 0;
}