BZOJ 2733 & splay的合并

/*==========================================================================
# Last modified: 2016-03-20 10:23
# Filename: 2733.cpp
# Description: 
==========================================================================*/
#define me AcrossTheSky 
#include <cstdio> 
#include <cmath> 
#include <ctime> 
#include <string> 
#include <cstring> 
#include <cstdlib> 
#include <iostream> 
#include <algorithm> 
  
#include <set> 
#include <map> 
#include <stack> 
#include <queue> 
#include <vector> 
 
#define lowbit(x) (x)&(-x) 
#define FOR(i,a,b) for((i)=(a);(i)<=(b);(i)++) 
#define FORP(i,a,b) for(int i=(a);i<=(b);i++) 
#define FORM(i,a,b) for(int i=(a);i>=(b);i--) 
#define ls(a,b) (((a)+(b)) << 1) 
#define rs(a,b) (((a)+(b)) >> 1) 
#define getlc(a) ch[(a)][0] 
#define getrc(a) ch[(a)][1] 
 
#define maxn 400000 
#define maxm 100000 
#define pi 3.1415926535898 
#define _e 2.718281828459 
#define INF 1070000000 
using namespace std; 
typedef long long ll; 
typedef unsigned long long ull; 
 
template<class T> inline 
void read(T& num) { 
    bool start=false,neg=false; 
    char c; 
    num=0; 
    while((c=getchar())!=EOF) { 
        if(c==‘-‘) start=neg=true; 
        else if(c>=‘0‘ && c<=‘9‘) { 
            start=true; 
            num=num*10+c-‘0‘; 
        } else if(start) break; 
    } 
    if(neg) num=-num; 
} 
/*==================split line==================*/ 
int ch[maxn][2],fa[maxn],father[maxn],sz[maxn],key[maxn];
void pushup(int x){ sz[x]=sz[ch[x][0]]+sz[ch[x][1]]+1; }
int kth(int x,int k){
	while (x){
		if (k==sz[ch[x][0]]+1) return x;
		if (k>sz[ch[x][0]]+1) k-=sz[ch[x][0]],k--,x=ch[x][1];
		else x=ch[x][0];
	}
}
int find(int x){
	return father[x]==x?x:find(father[x]);
}
void rotate(int x){
	int p=fa[x],q=fa[p],d=ch[p][1]==x;
	fa[ch[p][d]=ch[x][d^1]]=p; pushup(p);
	fa[ch[x][d^1]=p]=x;pushup(x);
	fa[x]=q;
	if (q){
		if (ch[q][1]==p) ch[q][1]=x;
		else ch[q][0]=x;
	}
}
void splay(int x,int aim){
	for (int y;(y=fa[x])!=aim;rotate(x))
		if (fa[y]!=aim)
			rotate((getlc(y)==x)==(getlc(fa[y])==y)?y:x);
}
void insert(int x,int root){
	int node=root;
	while (node){
		sz[node]++; 
		int &d=ch[node][key[node]<key[x]];
		if (d==0) {
			d=x; fa[x]=node; ch[x][0]=ch[x][1]=0; sz[x]=1; node=x; break;
		}
		node=d;
	}
	//splay(node,0);
}
int q[maxn];
void join(int x,int root){
	/*int lc=ch[x][0],rc=ch[x][1];
	ch[x][0]=ch[x][1]=0;
	if (lc) {
		join(lc,root);
	}
	 //ch[x][1]=0; fa[rc]=0;
	insert(x,root);
	if (rc) join(rc,root);*/
	int head=1,tail=1;
	q[head]=x;
	while (head<=tail){
		x=q[head]; head++;
		int lc=ch[x][0],rc=ch[x][1];
		ch[x][0]=ch[x][1]=0;
		insert(x,root);
		if (lc) q[++tail]=lc; 
		if (rc) q[++tail]=rc;
	}
} 
void Union(int x,int y){
	int u=find(x),v=find(y);
	if (u==v) return;
	else {
		father[u]=v;
		splay(u,0); splay(v,0);
		if (sz[u]<sz[v]) join(u,v);
			else join(v,u);/*father[u]=v;
		int a=kth(u,1),b=kth(v,sz[v]);
		splay(a,0); splay(b,0);
		if (key[a]<key[b]) {ch[a][1]=b; fa[b]=a; pushup(a);}
			else {ch[b][1]=a; fa[a]=b; pushup(b);}
		*/

	}
}
void query(int x,int k){
	splay(x,0);
	if (k>sz[x]) printf("-1\n");
	else printf("%d\n",kth(x,k));
}
int main(){
	int n,m; read(n); read(m);
	memset(father,0,sizeof(father));
	FORP(i,1,n) { read(key[i]); father[i]=i; sz[i]=1;}
	FORP(i,1,m){
		int u,v; read(u); read(v); Union(u,v);
	}
	int q; read(q);
	FORP(i,1,q){
		char ch[10]; scanf("%s",ch);
		if (ch[0]==‘Q‘) {
			int x,k; read(x); read(k);
			query(x,k);
		}
		else { int u,v; read(u); read(v); Union(u,v);}
	}
}