[NOI2015]软件包管理器-树链剖分

#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e6+5;
int n,m;
int e,begin[maxn],next[maxn],to[maxn],val[maxn];
struct segment_tree{
	int l,r,sum,mark;
}tree[maxn<<2];
int son[maxn],id[maxn],father[maxn],cnt,deep[maxn],size[maxn],top[maxn];
inline void add(int x,int y){
	to[++e] = y;
	next[e] = begin[x];
	begin[x] = e;
}
inline void dfs1(int x,int fa,int dep){
	deep[x] = dep;
	father[x] = fa;
	size[x] = 1;
	int maxson = -1;
	for(int i = begin[x];i;i = next[i]){
		int y = to[i];
		if(y == fa)continue;
		dfs1(y,x,dep+1);
		size[x] += size[y];
		if(size[y] > maxson)son[x] = y,maxson = size[y];
	}
}
inline void dfs2(int x,int ntop){
	id[x] = ++cnt;
	top[x] = ntop;
	if(!son[x])return;
	dfs2(son[x],ntop);
	for(int i = begin[x];i;i = next[i]){
		int y = to[i];
		if(y == father[x] || y == son[x])continue;
		dfs2(y,y);
	}
}
inline void pushup(int root){
	tree[root].sum = tree[root<<1].sum+tree[root<<1|1].sum;
}
inline void pushdown(int root){
	if (tree[root].mark){
		tree[root<<1].mark = tree[root].mark;
		tree[root<<1|1].mark = tree[root].mark;
		tree[root<<1].sum = (tree[root].mark-1)*(tree[root<<1].r-tree[root<<1].l+1);
		tree[root<<1|1].sum = (tree[root].mark-1)*(tree[root<<1|1].r-tree[root<<1|1].l+1);
		tree[root].mark = 0;
	}
}
inline void build(int l,int r,int root){
	tree[root].l = l;
	tree[root].r = r;
	if(l == r)return;
	int mid = l+r>>1;
	build(l,mid,root<<1);
	build(mid+1,r,root<<1|1);
	pushup(root);
}
inline void update(int l,int r,int ql,int qr,int root,int x){
	if(ql > r || qr < l)return;
	if(ql <= l && qr >= r){
		tree[root].mark = x+1;
		tree[root].sum = x*(r-l+1);
		return;
	}
	pushdown(root);
	int mid = l+r>>1;
	update(l,mid,ql,qr,root<<1,x);
	update(mid+1,r,ql,qr,root<<1|1,x);
	pushup(root);
}
inline int query(int l,int r,int ql,int qr,int root){
	if(ql > r || qr < l)return 0;
	if(ql <= l && qr >= r)return tree[root].sum;
	pushdown(root);
	int mid = l+r>>1;
	return query(l,mid,ql,qr,root<<1)+query(mid+1,r,ql,qr,root<<1|1);
}
inline int Query(int l,int r,int ql,int qr,int root){
	if(ql > r || qr < l)return 0;
	if(ql <= l && qr >= r)return (r-l+1)-tree[root].sum;
	pushdown(root);
	int mid = l+r>>1;
	return Query(l,mid,ql,qr,root<<1)+Query(mid+1,r,ql,qr,root<<1|1);
}
inline void update_range(int u,int v,long long x){
	while(top[u] != top[v]){
		if(deep[top[u]] < deep[top[v]])swap(u,v);
		update(1,cnt,id[top[u]],id[u],1,x);
		u = father[top[u]];
	}
	if(deep[u] > deep[v])swap(u,v);
	update(1,cnt,id[u],id[v],1,x);
}
inline int query_range(int u,int v){
	int ans = 0;
	while(top[u] != top[v]){
		if (deep[top[u]] < deep[top[v]])swap(u,v);
		ans += Query(1,cnt,id[top[u]],id[u],1);
		u = father[top[u]];
	}
	if(deep[u] > deep[v])swap(u,v);
	return ans+Query(1,cnt,id[u],id[v],1);
}
int main() {
	cin>>n;
	for(int i = 2,x;i <= n;i++){
		cin>>x;
		x++;
		add(x,i);
	}
	dfs1(1,0,1);
	dfs2(1,1);
	build(1,cnt,1);
	cin>>m;
	while(m--){
		string dispose;
		int x;
		cin>>dispose>>x;
		x++;
		if(dispose == "install"){
			cout<<query_range(1,x)<<endl;
			update_range(1,x,1);
		}
		else{
			cout<<query(1,cnt,id[x],id[x]+size[x]-1,1)<<endl;
			update(1,cnt,id[x],id[x]+size[x]-1,1,0);
		}
	}
	return 0;
}

　　树链剖分这东西我还是只会用一点点，所以讲不出来做法，有的题实在心态爆炸看别人代码会发现真的是细节决定成败，以后尽量可以把思路讲出来，现在的状况是：只可意会不可言传！！！~~~