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;
}