洛谷 P3258 [JLOI2014]松鼠的新家

题链

树剖板题

#include <bits/stdc++.h>
using namespace std;
#define ls rt<<1
#define rs rt<<1|1
#define LL long long
#define PI acos(-1.0)
#define eps 1e-8
#define Pair pair<double,double>
// notice
#define mod 998244353 
#define MAXN 2e6
#define MS 300009

LL n,m;
LL a[MS];
vector<LL > vc[MS];
LL fa[MS],sz[MS],dep[MS],zson[MS];
LL tot,top[MS],dfn[MS],w[MS];
LL p[MS<<2];
LL la[MS<<2];
LL ac[MS];

void dfs1(LL x,LL f){
	sz[x] = 1;
	dep[x] = dep[f]+1;
	fa[x] = f;
	int maxzson = 0;
	for(auto &i:vc[x]){
		if(i != f){
			dfs1(i,x);
			sz[x] += sz[i];
			if(sz[i] > maxzson){
				maxzson = sz[i];
				zson[x] = i;
			}
		}
	}
}

void dfs2(LL x,LL tp){
	dfn[x] = ++tot;
	top[x] = tp;
	w[x] = 0;
	if(zson[x]) dfs2(zson[x],tp);
	for(auto &i:vc[x]){
		if(i != fa[x] && i != zson[x]){
			dfs2(i,i);
		}
	}
}

void push_down(int rt){
	if(la[rt]){
		p[ls] += la[rt];
		p[rs] += la[rt];
		la[ls] += la[rt];
		la[rs] += la[rt];
		la[rt] = 0;
	}
}

void update(int L,int R,int l,int r,int rt,LL val){
	if(L <= l && r <= R){
		p[rt] += val;
		la[rt] += val;
		return;
	}
	push_down(rt);
	int m = l+r>>1;
	if(m >= L) update(L,R,l,m,ls,val);
	if(m <  R) update(L,R,m+1,r,rs,val);
}

LL query(int pos,int l,int r,int rt){
	if(l == r) return p[rt];
	int m = l+r>>1;
	push_down(rt);
	if(m >= pos) return query(pos,l,m,ls);
	else return query(pos,m+1,r,rs);
}

void op(LL x,LL y){
	while(top[x] != top[y]){
		if(dep[ top[x] ] < dep[ top[y] ]) swap(x,y);
		update(dfn[top[x]],dfn[x],1,n,1,1);
		x = fa[top[x]];
	}
	if(dep[x] > dep[y]) swap(x,y);
	update(dfn[x],dfn[y],1,n,1,1);
}

int main() {
	ios::sync_with_stdio(false);
	cin >> n;
	for(int i=1;i<=n;i++){
		cin >> a[i];
	}
	for(int i=2;i<=n;i++){
		LL u,v;
		cin >> u >> v;
		vc[u].push_back(v);
		vc[v].push_back(u);
	}
	dfs1(1,1);
	dfs2(1,1);
	for(int i=2;i<=n;i++){
		LL u = a[i-1];
		LL v = a[i];
		op(u,v);
		update(dfn[v],dfn[v],1,n,1,-1);
	}
	for(int i=1;i<=n;i++){
		LL ans = query(dfn[i],1,n,1);
		cout << ans << "\n";
	}
	

	return 0;
}