bzoj2733: [HNOI2012]永无乡（splay+启发式合并/线段树合并）

#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<queue>
#include<algorithm>
#define ll long long 
#define which(x) (son[fq[x]][1]==x)
using namespace std;
const int maxn=500010,extar[2]={-2147483647,2147483647};
int n,m,x,y,z,tot,q,cnt;
int fa[maxn],data[maxn],size[maxn],a[maxn],son[maxn][2],fq[maxn],id[maxn],root[maxn];
char ch[maxn];
void read(int &k)
{
    int f=1;k=0;char c=getchar();
    while(c<‘0‘||c>‘9‘)c==‘-‘&&(f=-1),c=getchar();
    while(c<=‘9‘&&c>=‘0‘)k=k*10+c-‘0‘,c=getchar();
    k*=f;
}
int gf(int x){return fa[x]==x?x:fa[x]=gf(fa[x]);}
int search(int x,int k)
{
    //printf("KPM%d %d %d\n",x,k,son[x][1]);
    if(data[x]<k&&son[x][1])return search(son[x][1],k);
    if(data[x]>k&&son[x][0])return search(son[x][0],k);
    return x;
}
void rotate(int x)
{
    int f=fq[x];bool k=which(x);
    son[f][k]=son[x][!k];
    son[x][!k]=f;
    son[fq[f]][which(f)]=x;
    fq[x]=fq[f];
    fq[f]=x;
    if(son[f][k])fq[son[f][k]]=f;
    size[x]=size[f];
    size[f]=size[son[f][0]]+size[son[f][1]]+1;    
    //printf("%d %d %d ORZCZL\n",x,f,size[x]);
}
void splay(int x)
{
    while(fq[x])
    {
        int f=fq[x];
        if(!fq[f])
        {
            rotate(x);
            break;
        }
        if(which(x)^which(f))rotate(x);
        else rotate(f);
        rotate(x);
    }
}
void insert(int &x,int w)
{
    //printf("%d %d\n",x,w);
    if(!x){x=++tot;data[tot]=a[w];size[tot]=1;id[x]=w;return;}
    int k=search(x,a[w]);
    //printf("qiguai%d %d %d\n",k,a[w],data[k]);
    //printf("QAQ");
    ++tot;
    data[tot]=a[w];fq[tot]=k;id[tot]=w;
    if(a[w]<data[k])son[k][0]=tot;
    else son[k][1]=tot;
    size[tot]=1;
    while(k)size[k]++,k=fq[k];
    splay(tot);
    x=tot;
}
int rank(int x,int k)
{
    //++cnt;
    //printf("%d %d %d\n",x,k,size[son[x][0]]);
    //if(cnt>10)exit(0);
    if(size[son[x][0]]>=k)return rank(son[x][0],k);
    if((size[son[x][0]]+1)==k)return x;
    return rank(son[x][1],k-size[son[x][0]]-1);
}
void merge(int x,int y)
{
    //printf("WUWUWU%d %d\n",x,y);
    if(son[x][0])merge(son[x][0],root[y]);
    insert(root[y],id[x]);
    if(son[x][1])merge(son[x][1],root[y]);
}
int main()
{
    read(n);read(m);
    for(int i=1;i<=n;i++)
    {
        read(a[i]);
        fa[i]=i;
    }
    //for(int i=1;i<=n;i++)printf("OAO%d\n",gf(i));
    for(int i=1;i<=m;i++)
    {
        read(x);read(y);
        fa[gf(x)]=gf(y);
    }
    //for(int i=1;i<=n;i++)printf("QAQ%d %d\n",gf(i),root[gf(i)]);
    //printf("\n");
    for(int i=1;i<=n;i++)insert(root[gf(i)],i);
    //for(int i=1;i<=n;i++)printf("QAQ%d %d\n",gf(i),root[gf(i)]);
    //printf("%dQQQQQQQQQQQQQQ\n",son[root[gf(1)]][0]);
    read(q);
    for(int i=1;i<=q;i++)
    {
        scanf("%s",ch);read(x);read(y);
        if(ch[0]==‘Q‘)
        {
            x=gf(x);
            //printf("%d %d\n",root[x],size[root[x]]);
            if(size[root[x]]<y)printf("-1\n");
            else 
            {
                int pos=rank(root[x],y);
                printf("%d\n",id[pos]),splay(pos),root[x]=pos;
            }
        }
        else
        {
            x=gf(x);y=gf(y);
            if(x!=y)
            {
                //printf("%d %d %d %d\n",root[x],root[y],size[root[x]],size[root[y]]);
                if(size[root[x]]>size[root[y]])swap(x,y);
                fa[x]=y;
                merge(root[x],y);
                root[x]=0;
            }
        }
    }
    return 0;
}