[bzoj2733] [HNOI2012]永无乡

Posted 2020-07-26 czllgzmzl

　　写了线段树合并。。具体合并姿势和可并堆基本一样。。

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cstring>
 4 #include<algorithm>
 5 using namespace std;
 6 const int maxn=100233,mxnode=maxn*20;
 7 int lc[mxnode],rc[mxnode],sz[mxnode],tot;
 8 int rt[maxn],fa[maxn],size[maxn];
 9 int val[maxn],id[maxn];
10 int i,j,k,n,m,ans,P,K;
11  
12 int ra;char rx;
13 inline int read(){
14     rx=getchar(),ra=0;
15     while(rx<\'0\'||rx>\'9\')rx=getchar();
16     while(rx>=\'0\'&&rx<=\'9\')ra*=10,ra+=rx-48,rx=getchar();return ra;
17 }
18  
19 int merge(int x,int y,int a,int b){
20     if(!x||!y)return x|y;
21     sz[x]+=sz[y];if(a==b)return x;
22     int mid=a+b>>1;
23     lc[x]=merge(lc[x],lc[y],a,mid),rc[x]=merge(rc[x],rc[y],mid+1,b);
24     return x;
25 }
26 void query(int x,int a,int b){
27     if(a==b){ans=id[a];return;}
28     int mid=a+b>>1;
29     if(K<=sz[lc[x]])query(lc[x],a,mid);else K-=sz[lc[x]],query(rc[x],mid+1,b);
30 }
31 void build(int &x,int a,int b){
32     x=++tot,sz[x]=1;
33     if(a==b)return;
34     int mid=a+b>>1;
35     if(P<=mid)build(lc[x],a,mid);else build(rc[x],mid+1,b);
36 }
37  
38 inline int getfa(int x){
39     return fa[x]!=x?fa[x]=getfa(fa[x]):x;
40 }
41 inline void con(int a,int b){
42     a=getfa(a),b=getfa(b);
43     if(a!=b)
44         fa[a]=b,rt[b]=merge(rt[b],rt[a],1,n),size[b]+=size[a];
45 }
46 int main(){
47     n=read(),m=read();
48     for(i=1;i<=n;i++)val[i]=read(),id[val[i]]=i,P=val[i],build(rt[i],1,n),fa[i]=i,size[i]=1;
49     for(i=1;i<=m;i++)con(read(),read());
50     m=read();char s[2];int x;
51     while(m--){
52         scanf("%s",s);
53         if(s[0]==\'B\')con(read(),read());else{
54             x=getfa(read()),K=read();
55             if(size[x]>=K)query(rt[x],1,n);else ans=-1;
56             printf("%d\\n",ans);
57         }
58     }
59     return 0;
60 }

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