SPOJ QTREE

　　https://www.spoj.pl/problems/QTREE/

　　Splay基础打得差不多之后，第一次搞LCT。

　　我的代码跟QZ的太像了囧，我发现我什么都是跟他学的，以至于我俩同时写一个数据结构题交上去就差不多会被判作弊……

　　

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <queue>
#define NIL LCT
#define MN 10001
#define MM 20001
#define INF 10000000
using namespace std;

queue<int> q;
int cases,n,pnt[MN],a,b,c;
char s[10];

struct EDGE{
	int pnt,index,cost;
	EDGE *pre;
	EDGE (){}
	EDGE(int _pnt,int _cost,EDGE *_pre,int _index):pnt(_pnt),cost(_cost),pre(_pre),index(_index){}
}Edge[MM],*EP=Edge,*edge[MM];

inline void addedge(int a,int b,int c,int index){
	edge[a]=new(++EP)EDGE(b,c,edge[a],index);
	edge[b]=new(++EP)EDGE(a,c,edge[b],index);
}

struct LinkCutTree{
	struct NODE{
		int val,maxv;
		bool root;
		NODE *left,*right,*father;
		NODE (){}
		NODE(int _val,NODE *_left,NODE *_right,NODE *_father):val(_val),left(_left),right(_right),father(_father){root=true;}
	}LCT[MN],*NP,*node[MN];
	
	void update(NODE *&t){
		t->maxv=max(t->val,max(t->left->maxv,t->right->maxv));
	}
	
	void init(){
		NP=NIL;
		NIL->val=NIL->maxv=-INF;
		NIL->left=NIL->right=NIL->father=NIL;
		NIL->root=false;
		memset(node,0,sizeof(node));
	}
	
	void build(){
		q.push(1);
		node[1]=new(++NP)NODE(-INF,NIL,NIL,NIL);
		while(!q.empty()){
			int i=q.front();q.pop();
			for(EDGE *j=edge[i];j;j=j->pre)
				if(node[j->pnt]!=node[i]->father){
					node[j->pnt]=new(++NP)NODE(j->cost,NIL,NIL,node[i]);
					pnt[j->index]=j->pnt;
					q.push(j->pnt);
				}
		}
	}
	
	void zig(NODE *&t){
		NODE *f=t->father,*r=t->right;
		t->father=f->father;
		if(f->root){
			t->root=true;
			f->root=false;
		}else{
			if(f->father->left==f) f->father->left=t;
			else f->father->right=t;
		}
		t->right=f,f->father=t,f->left=r,r->father=f;
		update(f);
	}
	
	void zag(NODE *&t){
		NODE *f=t->father,*l=t->left;
		t->father=f->father;
		if(f->root){
			t->root=true;
			f->root=false;
		}else{
			if(f->father->left==f) f->father->left=t;
			else f->father->right=t;
		}
		t->left=f;f->father=t,f->right=l,l->father=f;
		update(f);
	}
	
	void splay(NODE *&t){
		while(!t->root){
			if(t->father->root){
				if(t->father->left==t) zig(t);
				else zag(t);
			}else{
				if(t->father->father->left==t->father){
					if(t->father->left==t) zig(t->father),zig(t);
					else zag(t),zig(t);
				}else{
					if(t->father->left==t) zig(t),zag(t);
					else zag(t->father),zag(t);
				}
			}
		}
		update(t);
	}
	
	void Expose(NODE *&t){
		NODE *p=t,*q=NIL;
		while(p!=NIL){
			splay(p);
			p->right->root=true;
			p->right=q;
			p->right->root=false;
			update(p);
			q=p;p=p->father;
		}
	}
	
	void modify(int i,int key){
		node[i]->val=key;
		update(node[i]);
		splay(node[i]);
	}
	
	void query(int a,int b){
		Expose(node[a]);
		NODE *q=NIL,*p=node[b];
		while(p!=NIL){
			splay(p);
			if(p->father==NIL) printf("%d\n",max(p->right->maxv,q->maxv));
			p->right->root=true;
			p->right=q;
			p->right->root=false;
			update(p);
			q=p;p=p->father;
		}
	}
}tree;

void init(){
	EP=Edge;
	memset(edge,0,sizeof(edge));
	memset(pnt,0,sizeof(pnt));
}
		
int main(){
	scanf("%d",&cases);
	while(cases--){
		init();
		tree.init();
		scanf("%d",&n);
		for(int i=1;i<=n;i++){
			scanf("%d%d%d",&a,&b,&c);
			addedge(a,b,c,i);
		}
		tree.build();
		while(scanf("%s",s),s[0]!='D'){
			if(s[0]=='C'){
				scanf("%d%d",&a,&b);
				tree.modify(pnt[a],b);
			}else{
				scanf("%d%d",&a,&b);
				tree.query(a,b);
			}
		}
	}
	return 0;
}