luogu3178 [HAOI2015]树上操作

裸题

#include <iostream>
#include <cstdio>
using namespace std;
typedef long long ll;
int n, m, ecnt, hea[100005], dep[100005], top[100005], idx[100005], cnt;
int fa[100005], siz[100005], son[100005], uu, vv;
ll w[100005], wt[100005], ww;
struct Edge{
	int too, nxt;
}edge[200005];
void add_edge(int fro, int too){
	edge[++ecnt].nxt = hea[fro];
	edge[ecnt].too = too;
	hea[fro] = ecnt;
}
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)	continue;
		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] = ++cnt;
	wt[cnt] = w[x];
	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])	continue;
		dfs2(t, t);
	}
}
struct SGT{
	ll sum[400005];
	ll tag[400005];
	void build(int o, int l, int r){
		if(l==r)	sum[o] = wt[l];
		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] += tag[o] * (mid-l+1);
		sum[rson] += tag[o] * (r-mid);
		tag[o] = 0;
	}
	void update(int o, int l, int r, int x, int y, ll 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])	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];
		}
	}
	ll query(int o, int l, int r, int x, int y){
		if(l>=x && r<=y)	return sum[o];
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			ll ans=0;
			if(tag[o])	pushDown(o, l, r, lson, rson, mid);
			if(x<=mid)	ans += query(lson, l, mid, x, y);
			if(mid<y)	ans += query(rson, mid+1, r, x, y);
			return ans;
		}
	}
}sgt;
ll queryRange(int uu, int vv){
	ll ans=0;
	while(top[uu]!=top[vv]){
		if(dep[top[uu]]<dep[top[vv]])	swap(uu, vv);
		ans += sgt.query(1, 1, n, idx[top[uu]], idx[uu]);
		uu = fa[top[uu]];
	}
	if(dep[uu]>dep[vv])	swap(uu, vv);
	ans += sgt.query(1, 1, n, idx[uu], idx[vv]);
	return ans;
}
signed main(){
	cin>>n>>m;
	for(int i=1; i<=n; i++)
		scanf("%lld", &w[i]);
	for(int i=1; i<n; i++){
		scanf("%d %d", &uu, &vv);
		add_edge(uu, vv);
		add_edge(vv, uu);
	}
	dep[1] = 1;
	dfs1(1, 0);
	dfs2(1, 1);
	sgt.build(1, 1, n);
	while(m--){
		scanf("%d", &uu);
		if(uu==1){
			scanf("%d %lld", &vv, &ww);
			sgt.update(1, 1, n, idx[vv], idx[vv], ww);
		}
		if(uu==2){
			scanf("%d %lld", &vv, &ww);
			sgt.update(1, 1, n, idx[vv], idx[vv]+siz[vv]-1, ww);
		}
		if(uu==3){
			scanf("%d", &vv);
			printf("%lld
", queryRange(1, vv));
		}
	}
	return 0;
}