[bzoj2733] [HNOI2012]永无乡
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 }
