[luogu4315]月下“毛景树”

[luogu4315]月下“毛景树”

luogu
联赛前复习一发树剖.不会告诉你WA了4发

#define ls x<<1,l,mid
#define rs x<<1|1,mid+1,r
#include<bits/stdc++.h>
using namespace std;
const int _=1e5+5;
int re(){
	int x=0,w=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
	return x*w;
}
int n,cnt,ans,ts;
int mx[_<<2],tag[_<<2],cov[_<<2];
int h[_],dfn[_],val[_],son[_],id[_],sz[_],fa[_],dep[_],t[_],f[_];
struct edge{int to,next,w,id;}e[_<<1];
void link(int u,int v,int w,int id){
	e[++cnt]=(edge){v,h[u],w,id};h[u]=cnt;
	e[++cnt]=(edge){u,h[v],w,id};h[v]=cnt;
}
void dfs(int u){
	sz[u]=1;
	for(int i=h[u];i;i=e[i].next){
		int v=e[i].to;
		if(v==fa[u])continue;
		fa[v]=u;dep[v]=dep[u]+1;f[e[i].id]=v;
		dfs(v);sz[u]+=sz[v];val[v]=e[i].w;
		if(sz[v]>sz[son[u]])son[u]=v;
	}
}
void dfs(int u,int tp){
	t[u]=tp;dfn[u]=++ts;id[ts]=u;
	if(son[u])dfs(son[u],tp);
	for(int i=h[u];i;i=e[i].next){
		int v=e[i].to;
		if(v^son[u]&&v^fa[u])dfs(v,v);
	}
}
void pu(int x){mx[x]=max(mx[x<<1],mx[x<<1|1]);}
void pt(int x,int v){mx[x]+=v;tag[x]+=v;}
void cv(int x,int v){mx[x]=v;cov[x]=v;tag[x]=0;}
void pd(int x){
	if(cov[x])cv(x<<1,cov[x]),cv(x<<1|1,cov[x]),cov[x]=0;
	if(tag[x])pt(x<<1,tag[x]),pt(x<<1|1,tag[x]),tag[x]=0;
}
void bu(int x,int l,int r){
	if(l==r){mx[x]=val[id[l]];return;}
	int mid=l+r>>1;bu(ls);bu(rs);pu(x);
}
void mem(int x,int l,int r,int ql,int qr,int v){
	if(ql<=l&&r<=qr){cv(x,v);return;}pd(x);
	int mid=l+r>>1;if(ql<=mid)mem(ls,ql,qr,v);
	if(qr>mid)mem(rs,ql,qr,v);pu(x);
}
void add(int x,int l,int r,int ql,int qr,int v){
	if(ql<=l&&r<=qr){pt(x,v);return;}pd(x);
	int mid=l+r>>1;if(ql<=mid)add(ls,ql,qr,v);
	if(qr>mid)add(rs,ql,qr,v);pu(x);
}
int qmax(int x,int l,int r,int ql,int qr){
	if(ql<=l&&r<=qr)return mx[x];pd(x);int mid=l+r>>1;
	int res=-1e9;if(ql<=mid)res=qmax(ls,ql,qr);
	if(qr>mid)res=max(res,qmax(rs,ql,qr));return res;
}
void solve(int u,int v,int w,int o){
	while(t[u]^t[v]){
		if(dep[t[u]]<dep[t[v]])swap(u,v);
		if(o==1)add(1,1,n,dfn[t[u]],dfn[u],w);
		if(!o)mem(1,1,n,dfn[t[u]],dfn[u],w);
		if(o==2)ans=max(ans,qmax(1,1,n,dfn[t[u]],dfn[u]));
		u=fa[t[u]];
	}
	if(u==v)return;
	if(dep[u]<dep[v])swap(u,v);
	if(o==1)add(1,1,n,dfn[v]+1,dfn[u],w);
	if(!o)mem(1,1,n,dfn[v]+1,dfn[u],w);
	if(o==2)ans=max(ans,qmax(1,1,n,dfn[v]+1,dfn[u]));
}
int main(){
	n=re();
	for(int i=1,u,v,w;i<n;i++){
		u=re(),v=re(),w=re();
		link(u,v,w,i);
	}
	dfs(1);dfs(1,1);bu(1,1,n);
	char op[8];int u,v;
	while(1){
		scanf("%s",op);
		if(op[1]=='t')break;
		u=re(),v=re();
		if(op[1]=='o')solve(u,v,re(),0);
		if(op[1]=='d')solve(u,v,re(),1);
		if(op[1]=='a'){ans=-1e9;solve(u,v,0,2);printf("%d
",ans);}
		if(op[1]=='h')mem(1,1,n,dfn[f[u]],dfn[f[u]],v);
	}
	return 0;
}