UVA 1479 Graph and Queries(Treap树)

首先把最终图弄出来，然后逆序命令即可。

#include<cstdlib>struct Node{    Node *ch[2];    int v,r,s;    Node(int v): v(v) {ch[0]=ch[1]=NULL;r=rand();s=1;}    int cmp(int x) const {        if(x==v) return -1;        return x<v?0:1;    }    void maintain(){        s=1;        if(ch[0]!=NULL) s+=ch[0]->s;        if(ch[1]!=NULL) s+=ch[1]->s;    }};void rotate(Node* &o,int d){    Node *k=o->ch[d^1];o->ch[d^1]=k->ch[d];k->ch[d]=o;    o->maintain();k->maintain();o=k;}void insert(Node* &o,int x){    if(o==NULL) o=new Node(x);    else{        int d=(x<o->v)?0:1;        insert(o->ch[d],x);        if(o->ch[d]->r>o->r) rotate(o,d^1);    }    o->maintain();}void remove(Node* &o,int x){    int d=o->cmp(x);    if(d==-1)    {        Node* u=o;        if(o->ch[0]!=NULL&&o->ch[1]!=NULL)        {            int d2=(o->ch[0]->r<o->ch[1]->r)?1:0;            rotate(o,d2);remove(o->ch[d2],x);        }        else{            if(o->ch[0]==NULL) o=o->ch[1];else o=o->ch[0];            delete u;        }    }    else remove(o->ch[d],x);    if(o!=NULL) o->maintain();}#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int maxn=20000+10;const int maxm=60000+10;const int maxc=500000+10;struct Command{    char type;    int x,p;}commands[maxc];int n,m,weight[maxn],from[maxm],to[maxm],removed[maxm];int pa[maxn];Node* root[maxn];int findset(int x) {return pa[x]==x?x:pa[x]=findset(pa[x]);}int kth(Node* o,int k){    if(o==NULL||o->s<k||k<=0) return 0;    int s=(o->ch[1]==NULL)?0:o->ch[1]->s;    if(k==s+1) return o->v;    else if(k<=s) return kth(o->ch[1],k);    else return kth(o->ch[0],k-1-s);}void mergeto(Node* &src,Node* &dest){    if(src->ch[0]!=NULL) mergeto(src->ch[0],dest);    if(src->ch[1]!=NULL) mergeto(src->ch[1],dest);    insert(dest,src->v);    delete src;    src=NULL;}void removetree(Node* &x){    if(x->ch[0]!=NULL) removetree(x->ch[0]);    if(x->ch[1]!=NULL) removetree(x->ch[1]);    delete x;    x=NULL;}void add_edge(int x){    int u=findset(from[x]),v=findset(to[x]);    if(u!=v)    {        if(root[u]->s<root[v]->s) {pa[u]=v;mergeto(root[u],root[v]);}        else {pa[v]=u;mergeto(root[v],root[u]);}    }}int query_cnt;long long query_tot;void query(int x,int k){    query_cnt++;    query_tot+=kth(root[findset(x)],k);}void change_weight(int x,int v){    int u=findset(x);    remove(root[u],weight[x]);    insert(root[u],v);    weight[x]=v;}int main(){    int kase=0;    while(scanf("%d%d",&n,&m)&&(n+m))    {        for(int i=1;i<=n;i++) scanf("%d",&weight[i]);        for(int i=1;i<=m;i++) scanf("%d%d",&from[i],&to[i]);        memset(removed,0,sizeof(removed));        int c=0;        while(true)        {            char type;            int x,p=0,v=0;            scanf(" %c",&type);            if(type=='E') break;            scanf("%d",&x);            if(type=='D') removed[x]=1;            if(type=='Q') scanf("%d",&p);            if(type=='C'){                scanf("%d",&v);                p=weight[x];                weight[x]=v;            }            commands[c++]=(Command){type,x,p};        }                for(int i=1;i<=n;i++)        {            pa[i]=i;if(root[i]!=NULL) removetree(root[i]);            root[i]=new Node(weight[i]);        }        for(int i=1;i<=m;i++) if(!removed[i]) add_edge(i);        query_cnt=query_tot=0;        for(int i=c-1;i>=0;i--)        {            if(commands[i].type=='D') add_edge(commands[i].x);            if(commands[i].type=='C') change_weight(commands[i].x,commands[i].p);            if(commands[i].type=='Q') query(commands[i].x,commands[i].p);        }        printf("Case %d: %.6f\n",++kase,query_tot/(double)query_cnt);    }    return 0;}