UVA1479 Graph and Queries

思路

恶心人的题目
还是类似永无乡一题的Treap启发式合并思路
但是由于加边变成了删边
所以应该离线后倒序处理
数组要开够

代码

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#include <set>
#include <stack>
using namespace std;
int Nodecnt=0,root[250000*2],fa[250000*2],w_p[250000*2],cnt,n,m;
struct Edge{
    int u,v;
}E[250000*2];
struct oper{
    int opt,x,k,v;
}Ask[250000*2];
struct Node{
    int lson,rson,sz,val,ran;
}Treap[250000*2];
set<int> use;
stack<int> ans;
int find(int x){
    if(fa[x]==x)
        return x;
    else
        return fa[x]=find(fa[x]);
}
queue<int> q;
void throwin(int x){
    q.push(x);
}
int getnew(int val){
    int o;
    if(q.size())
        o=q.front(),q.pop();
    else
        o=++Nodecnt;
    Treap[o].lson=Treap[o].rson=0;
    Treap[o].sz=1;
    Treap[o].ran=rand();
    Treap[o].val=val;
    return o;
}
void pushup(int o){
    Treap[o].sz=Treap[Treap[o].lson].sz+Treap[Treap[o].rson].sz+1;
}
void rorateL(int &o){
    int x=Treap[o].rson;
    Treap[o].rson=Treap[x].lson;
    Treap[x].lson=o;
    pushup(o);
    pushup(x);
    o=x;
}
void rorateR(int &o){
    int x=Treap[o].lson;
    Treap[o].lson=Treap[x].rson;
    Treap[x].rson=o;
    pushup(o);
    pushup(x);
    o=x;
}
void insert(int val,int &o){
    if(!o){
        o=getnew(val);
        return;
    }
    Treap[o].sz++;
    if(val<=Treap[o].val){
        insert(val,Treap[o].lson);
        if(Treap[Treap[o].lson].ran<Treap[o].ran)
            rorateR(o);
    }
    else{
        insert(val,Treap[o].rson);
        if(Treap[Treap[o].rson].ran<Treap[o].ran)
            rorateL(o);
    }
}
void del(int val,int &o){
    if(o==0)
        return;
    if(Treap[o].val==val){
        if(Treap[o].lson*Treap[o].rson==0){
            throwin(o);
            o=Treap[o].lson+Treap[o].rson;
            return;
        }
        else{
            if(Treap[Treap[o].lson].ran<Treap[Treap[o].rson].ran){
                rorateR(o);
                Treap[o].sz--;
                del(val,Treap[o].rson);
                return;
            }
            else{
                rorateL(o);
                Treap[o].sz--;
                del(val,Treap[o].lson);
                return;
            }
        }
    }
    else if(val<Treap[o].val){
        Treap[o].sz--;
        del(val,Treap[o].lson);
        return;
    }
    else{
        Treap[o].sz--;
        del(val,Treap[o].rson);
        return;
    }
}
int query(int val,int o){
    if(!o)
        return 0;
    if(val==Treap[Treap[o].rson].sz+1)
        return Treap[o].val;
    else if(val>Treap[Treap[o].rson].sz+1)
        return query(val-Treap[Treap[o].rson].sz-1,Treap[o].lson);
    else
        return query(val,Treap[o].rson);
}
void dfs(int &o,int to){
    if(!o)
        return;
    insert(Treap[o].val,root[to]);
    dfs(Treap[o].lson,to);
    dfs(Treap[o].rson,to);
    throwin(o);
    o=0;
}
void init(void){
    Nodecnt=0;
    cnt=0;
    memset(Treap,0,sizeof(Treap));
    memset(root,0,sizeof(root));
    memset(fa,0,sizeof(fa));
    memset(w_p,0,sizeof(w_p));
    memset(E,0,sizeof(E));
    memset(Ask,0,sizeof(Ask));
    while(!q.empty())
        q.pop();
    use.clear();
}
int main(){
    freopen("test.in","r",stdin);
    freopen("test.out","w",stdout);
    int inq=0;
    while(scanf("%d %d",&n,&m)==2){
        inq++;
        if(n==0&&m==0)
            break;
        init();
        for(int i=1;i<=n;i++){
            scanf("%d",&w_p[i]);
            fa[i]=i;
        }  
        for(int i=1;i<=m;i++)
            scanf("%d %d",&E[i].u,&E[i].v),use.insert(i);
        char opt=getchar();
        while(opt!='E'&&opt!='Q'&&opt!='C'&&opt!='D')
            opt=getchar();
        while(opt!='E'){
            ++cnt;
            if(opt=='D'){
                Ask[cnt].opt=1;
                scanf("%d",&Ask[cnt].x);
                use.erase(Ask[cnt].x);
            }
            else if(opt=='Q'){
                Ask[cnt].opt=2;
                scanf("%d %d",&Ask[cnt].x,&Ask[cnt].k);
            }
            else if(opt=='C'){
                Ask[cnt].opt=3;
                scanf("%d %d",&Ask[cnt].x,&Ask[cnt].v);
                int t=w_p[Ask[cnt].x];
                w_p[Ask[cnt].x]=Ask[cnt].v;
                Ask[cnt].v=t;
            }
            opt=getchar();
            while(opt!='E'&&opt!='Q'&&opt!='C'&&opt!='D')
                opt=getchar();
        }
        for(int i=1;i<=n;i++)
            insert(w_p[i],root[i]);
        for(auto it = use.begin();it!=use.end();it++){
            int a=E[(*it)].u,b=E[(*it)].v;
            if(find(a)!=find(b)){
                if(Treap[root[find(a)]].sz<Treap[root[find(b)]].sz){
                    dfs(root[find(a)],find(b));
                    fa[find(a)]=find(b);
                }
                else{
                    dfs(root[find(b)],find(a));
                    fa[find(b)]=find(a);
                }
            }
        }
        for(int i=cnt;i>=1;i--){
            if(Ask[i].opt==1){
                int a=E[Ask[i].x].u,b=E[Ask[i].x].v;
                if(find(a)!=find(b)){
                    if(Treap[root[find(a)]].sz<Treap[root[find(b)]].sz){
                        dfs(root[find(a)],find(b));
                        fa[find(a)]=find(b);
                    }
                    else{
                        dfs(root[find(b)],find(a));
                        fa[find(b)]=find(a);
                    }
                } 
            }
            else if(Ask[i].opt==2){
                ans.push(query(Ask[i].k,root[find(Ask[i].x)]));
            }
            else{
                del(w_p[Ask[i].x],root[find(Ask[i].x)]);
                w_p[Ask[i].x]=Ask[i].v;
                insert(w_p[Ask[i].x],root[find(Ask[i].x)]);
            }
        }
        double mid=0.0;
        int qqq=0;
        while(!ans.empty()){
            qqq++;
            // printf("%d\n",ans.top());
            mid+=ans.top();
            ans.pop();
        }
        printf("Case %d: %.6lf\n",inq,mid/qqq);
    }
    return 0;
}