传送门-->http://www.lydsy.com/JudgeOnline/problem.php?id=3545
sb题
离线做，把边和询问都排序，然后一条条加边，维护连通块，于是这就是个平衡树合并裸题。。然而只有我这种都比被卡了辣么久- =
一发5s，感觉跑好慢……，一看榜，发现rank3而且代码也很短2333
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | #include<cstring>#include<cstdio>#include<algorithm>using namespace std;#define nc() getchar()inline int read(){ int x=0;char ch=nc();for(;ch<'0'||ch>'9';ch=nc()); for(;ch<='9'&&ch>='0';x=x*10+ch-48,ch=nc());return x;}#define N 100010int i,j,k,m,n,x,y,Q,h[N],cnt,fa[N],pp[N],ans[N*5],top;struct edge{ int x,y,z; inline void in(){x=read(),y=read(),z=read();} bool operator <(const edge&a)const{return z<a.z;} }e[N*5];struct ques{ int v,x,k,id; inline void in(){v=read(),x=read(),k=read(),id=i;} bool operator <(const ques&a)const{return x<a.x;}}q[N*5];int find(int x){return x==fa[x]?x:fa[x]=find(fa[x]);}struct node{ node*ch[2];int r,sz,h,id;inline void up(){sz=ch[0]->sz+ch[1]->sz+1;} inline int cmp(int x)const{return x>h;}}C[N],Null,*null=&Null;inline void rotate(node*&o,int d){node*k=o->ch[d^1];o->ch[d^1]=k->ch[d],k->ch[d]=o,k->sz=o->sz,o->up(),o=k;}int insert(node*&o,int x,int id){ if(o==null)o=&C[id],o->id=id,o->h=x,o->ch[0]=o->ch[1]=null,o->sz=1,o->r=rand(); else{ int d=o->cmp(x);++o->sz; insert(o->ch[d],x,id);if(o->ch[d]->r>o->r)rotate(o,d^1); } return o->id;}void Add(node*x,node*y){if(x==null)return;Add(x->ch[0],y),Add(x->ch[1],y),top=insert(y=&(C[top]),x->h,x->id);}inline void link(int u,int v){ if(u==v)return; if((C+u)->sz<(C+v)->sz)swap(u,v); fa[v]=u,top=pp[u],Add(C+pp[v],C+pp[u]),pp[u]=top;}int kth(node*o,int k){ if(o==null||k<=0||k>o->sz)return 0x7f7f7f7f; if(k<=o->ch[0]->sz)return kth(o->ch[0],k); if(k>o->ch[0]->sz+1)return kth(o->ch[1],k-o->ch[0]->sz-1); return o->h;}int main(){ for(n=read(),m=read(),Q=read(),i=1;i<=n;++i)h[i]=read(),fa[i]=i,pp[i]=i,(C+i)->id=i,(C+i)->h=h[i],(C+i)->sz=1,(C+i)->ch[0]=(C+i)->ch[1]=null,(C+i)->r=rand(); for(i=1;i<=m;++i)e[i].in();for(i=1;i<=Q;++i)q[i].in(); for(cnt=1,sort(e+1,e+m+1),sort(q+1,q+Q+1),i=1;i<=Q;++i){ while(e[cnt].z<=q[i].x&&cnt<=m)link(find(e[cnt].x),find(e[cnt].y)),++cnt; ans[q[i].id]=kth(C+pp[find(q[i].v)],(C+pp[find(q[i].v)])->sz-q[i].k+1); } for(i=1;i<=Q;++i)if(ans[i]==0x7f7f7f7f)puts("-1");else printf("%d\n",ans[i]);} |
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