luogu2146 [NOI2015]软件包管理器

安装就把根节点到它全设为 1

删除就把以它为根的子树全设为 0

记得标记初始化为-1，因为标记是 0 的情况也是要处理的。

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int n, m, uu, hea[100005], cnt, dep[100005], fa[100005], son[100005], siz[100005];
int top[100005], idx[100005], qwq;
char ss[15];
struct Edge{
	int too, nxt;
}edge[200005];
struct SGT{
	int sum[400005], tag[400005];
	void build(int o, int l, int r){
		tag[o] = -1;
		if(l==r)	sum[o] = 0;
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			if(l<=mid)	build(lson, l, mid);
			if(mid<r)	build(rson, mid+1, r);
			sum[o] = sum[lson] + sum[rson];
		}
	}
	void pushDown(int o, int l, int r, int lson, int rson, int mid){
		tag[lson] = tag[o];
		tag[rson] = tag[o];
		sum[lson] = (mid-l+1) * tag[o];
		sum[rson] = (r-mid) * tag[o];
		tag[o] = -1;
	}
	void update(int o, int l, int r, int x, int y, int k){
		if(l>=x && r<=y){
			sum[o] = (r-l+1) * k;
			tag[o] = k;
		}
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			if(tag[o]!=-1)	pushDown(o, l, r, lson, rson, mid);
			if(x<=mid)	update(lson, l, mid, x, y, k);
			if(mid<y)	update(rson, mid+1, r, x, y, k);
			sum[o] = sum[lson] + sum[rson];
		}
	}
}sgt;
void add_edge(int fro, int too){
	edge[++cnt].nxt = hea[fro];
	edge[cnt].too = too;
	hea[fro] = cnt;
}
void dfs1(int x, int f){
	dep[x] = dep[f] + 1;
	fa[x] = f;
	siz[x] = 1;
	int maxSon=-1;
	for(int i=hea[x]; i; i=edge[i].nxt){
		int t=edge[i].too;
		if(t!=f){
			dfs1(t, x);
			siz[x] += siz[t];
			if(siz[t]>maxSon)	maxSon = siz[t], son[x] = t;
		}
	}
}
void dfs2(int x, int topf){
	top[x] = topf;
	idx[x] = ++qwq;
	if(!son[x])	return ;
	dfs2(son[x], topf);
	for(int i=hea[x]; i; i=edge[i].nxt){
		int t=edge[i].too;
		if(t!=fa[x] && t!=son[x])
			dfs2(t, t);
	}
}
void upd(int xx, int yy){
	while(top[xx]!=top[yy]){
		if(dep[top[xx]]<dep[top[yy]])	swap(xx, yy);
		sgt.update(1, 1, n, idx[top[xx]], idx[xx], 1);
		xx = fa[top[xx]];
	}
	if(dep[xx]>dep[yy])	swap(xx, yy);
	sgt.update(1, 1, n, idx[xx], idx[yy], 1);
}
int main(){
	cin>>n;
	for(int i=2; i<=n; i++){
		scanf("%d", &uu);
		add_edge(i, uu+1);
		add_edge(uu+1, i);
	}
	dfs1(1, 0);
	dfs2(1, 1);
	sgt.build(1, 1, n);
	cin>>m;
	while(m--){
		scanf("%s %d", ss, &uu);
		uu++;
		if(ss[0]=='i'){
			int tmp=sgt.sum[1];
			upd(1, uu);
			printf("%d\n", sgt.sum[1]-tmp);
		}
		else{
			int tmp=sgt.sum[1];
			sgt.update(1, 1, n, idx[uu], idx[uu]+siz[uu]-1, 0);
			printf("%d\n", tmp-sgt.sum[1]);
		}
	}
	return 0;
}