【BZOJ4736】【清华集训2016】—温暖会指引我们前行（LCT）

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LCT维护一下$sum$和温度最值维护一下最小大成树就可以了

#include<bits/stdc++.h>
using namespace std;
const int RLEN=1<<20|1;
inline char gc(){
	static char ibuf[RLEN],*ob,*ib;
	(ob==ib)&&(ob=(ib=ibuf)+fread(ibuf,1,RLEN,stdin));
	return (ob==ib)?EOF:*ib++;
}
#define gc getchar
inline int read(){
	char ch=gc();
	int res=0,f=1;
	while(!isdigit(ch))f^=ch=='-',ch=gc();
	while(isdigit(ch))res=(res+(res<<2)<<1)+(ch^48),ch=gc();
	return f?res:-res;
}
const int N=400005;
int a[N],tp[N],val[N];
struct edge{
	int u,v;
}e[N];
namespace Lct{
	int q[N],fa[N],son[N][2],rev[N],pos[N],sum[N];
	#define lc(u) son[u][0]
	#define rc(u) son[u][1]
	inline bool isrt(int u){
		if(!fa[u])return 1;
		return lc(fa[u])!=u&&rc(fa[u])!=u;
	}
	inline bool isrc(int u){
		return rc(fa[u])==u;
	}
	inline void pushup(int u){
		pos[u]=u,sum[u]=val[u]+sum[lc(u)]+sum[rc(u)];
		if(lc(u)&&tp[pos[u]]>tp[pos[lc(u)]])pos[u]=pos[lc(u)];
		if(rc(u)&&tp[pos[u]]>tp[pos[rc(u)]])pos[u]=pos[rc(u)];
	}
	inline void pushdown(int u){
		if(!rev[u])return;
		if(lc(u))rev[lc(u)]^=1;
		if(rc(u))rev[rc(u)]^=1;
		swap(lc(u),rc(u)),rev[u]=0;
	}
	inline void rotate(int v){
		int u=fa[v],z=fa[u];
		int t=rc(u)==v;
		if(!isrt(u))son[z][rc(z)==u]=v;
		fa[v]=z;
		son[u][t]=son[v][t^1];
		fa[son[v][t^1]]=u;
		fa[u]=v,son[v][t^1]=u;
		pushup(u),pushup(v);
	}
	inline void splay(int u){
		q[q[0]=1]=u;
		for(int v=u;!isrt(v);v=fa[v])q[++q[0]]=fa[v];
		for(int i=q[0];i;i--)pushdown(q[i]);
		while(!isrt(u)){
			if(!isrt(fa[u]))
				isrc(u)==isrc(fa[u])?rotate(fa[u]):rotate(u);
			rotate(u);
		}
	}
	inline void access(int u){
		for(int v=0;u;v=u,u=fa[u]){
			splay(u),rc(u)=v;if(v)fa[v]=u;pushup(u);
		}
	}
	inline void makert(int u){
		access(u),splay(u),rev[u]^=1;
	}
	inline void link(int u,int v){
		makert(u),splay(v),fa[u]=v,pushup(v);
	}
	inline void cut(int u,int v){
		makert(u),access(v),splay(v),lc(v)=fa[u]=0;
	}
	inline int findrt(int u){
		access(u),splay(u);while(pushdown(u),lc(u))u=lc(u);
		splay(u);return u;
	}
}
using namespace Lct;
char op[10];
int n,m;
int f[N];
inline int find(int x){
	return f[x]==x?x:f[x]=find(f[x]);
}
int main(){
	n=read(),m=read();
	for(int i=1;i<=n;i++)tp[i]=2e9,f[i]=i;
	while(m--){
		scanf("%s",op);
		if(op[0]=='f'){
			int id=read()+n+1,u=read()+1,v=read()+1;
			e[id].u=u,e[id].v=v,tp[id]=read(),val[id]=read();
			if(find(u)!=find(v)){
				link(id,u);f[u]=v;
				link(id,v);
			}
			else{
				makert(u),access(v),splay(v);
				if(tp[pos[v]]<tp[id]){
					int p=pos[v];
					cut(p,e[p].u),cut(p,e[p].v);
					link(id,u),link(id,v);
				}
			}
		}
		else if(op[0]=='m'){
			int u=read()+1,v=read()+1;
			if(find(u)!=find(v))puts("-1");
			else{
				makert(u),access(v),splay(v);
				cout<<sum[v]<<'
';
			}
		}
		else{
			int u=read()+n+1,k=read();
			makert(u),splay(u),val[u]=k,pushup(u);
		}
	}
}