bzoj3779: 重组病毒 link-cut-tree

题目传送门

这道题看了做了个神转换.....推荐个博客给各位大爷看看吧神犇传送门

代码敲了半天....题目也读了半天 线段树维护的东西很容易和lct混在一起 调了调能过也是很开心啊 运气比较好吧233

#include<cstdio>
#include<cstring>
#include<algorithm>
#define LL long long 
using namespace std;
const int M=1<<17;
int read(){
    int ans=0,f=1,c=getchar();
    while(c<'0'||c>'9'){if(c=='-') f=-1; c=getchar();}
    while(c>='0'&&c<='9'){ans=ans*10+(c-'0'); c=getchar();}
    return ans*f;
}
int n,m,rt;
int next[M],sum,father[M],deep[M],first[M],second[M];
struct Edge{int u,v,from;}e[2*M];
void ins(int a,int b){sum++; e[sum].u=a; e[sum].v=b; e[sum].from=next[a]; next[a]=sum;}
void insert(int a,int b){ins(a,b); ins(b,a);}
struct node{int l,r; LL sum,tag;}tr[M*2];
int c[M][2],fa[M],dfsum,rev[M];
void build(int x,int l,int r){
    tr[x].l=l; tr[x].r=r;
    if(l==r) return ;
    int mid=(l+r)>>1;
    build(x<<1,l,mid); build(x<<1^1,mid+1,r);
}
void cal(int x,int w){tr[x].sum+=1LL*(tr[x].r-tr[x].l+1)*w;}
void push_up(int x){tr[x].sum=tr[x<<1].sum+tr[x<<1^1].sum;}
void push_down(int x){
    if(!tr[x].tag) return ;
    int w=tr[x].tag; tr[x].tag=0;
    int l=x<<1,r=x<<1^1;
    tr[l].tag+=w; cal(l,w);
    tr[r].tag+=w; cal(r,w);
}
void push_add(int x,int L,int R,int w){
    if(L>R) return ;
    if(L<=tr[x].l&&tr[x].r<=R){
        cal(x,w); 
        tr[x].tag+=1LL*w; return ;
    }
    if(tr[x].l==tr[x].r) return ;
    push_down(x);
    int mid=(tr[x].l+tr[x].r)>>1;
    if(L<=mid) push_add(x<<1,L,R,w);
    if(R>mid) push_add(x<<1^1,L,R,w);
    push_up(x);
}
LL push_ans(int x,int L,int R){
    if(L>R) return 0;
    if(L<=tr[x].l&&tr[x].r<=R) return tr[x].sum;
    //if(tr[x].l==tr[x].r) return 0;
    LL ans=0; push_down(x);
    int mid=(tr[x].l+tr[x].r)>>1;
    if(L<=mid) ans+=push_ans(x<<1,L,R);
    if(R>mid) ans+=push_ans(x<<1^1,L,R);
    return ans;
}
void dfs(int x,int old){
    father[x]=fa[x]=old;
    first[x]=++dfsum;
    deep[x]=deep[old]+1;
    push_add(1,first[x],first[x],deep[x]);
    for(int i=next[x];i;i=e[i].from) if(e[i].v!=old) dfs(e[i].v,x);
    second[x]=dfsum;
}
bool isrt(int x){return !x||(c[fa[x]][0]!=x&&c[fa[x]][1]!=x);}//0也算
void down(int x){
    if(!rev[x]) return ;
    rev[x]=0;
    int l=c[x][0],r=c[x][1];
    if(l) swap(c[l][0],c[l][1]),rev[l]^=1;    
    if(r) swap(c[r][0],c[r][1]),rev[r]^=1;        
}
void rotate(int x){
    int y=fa[x],z=fa[y],l=0,r=1;
    if(c[y][1]==x) l=1,r=0;
    if(!isrt(y)) c[z][c[z][1]==y]=x;
    fa[y]=x; fa[x]=z; fa[c[x][r]]=y;
    c[y][l]=c[x][r]; c[x][r]=y;
}
int st[M],top;
void splay(int x){
    st[++top]=x; for(int i=x;!isrt(i);i=fa[i])  st[++top]=fa[i];
    while(top) down(st[top--]);
    while(!isrt(x)){
        int y=fa[x],z=fa[y];
        if(!isrt(y)){
            if(c[z][0]==y^c[y][0]==x) rotate(x);
            else rotate(y);
        }
        rotate(x);
    }
}
bool inson(int x,int y){return first[x]<=first[y]&&second[y]<=second[x];}
int wson(int x,int y){
    for(int i=next[x];i;i=e[i].from) if(e[i].v!=father[x])
        if(first[e[i].v]<=first[y]&&second[y]<=second[e[i].v]) return e[i].v;
    return 0;
}
void add(int x,int w){
    if(x==rt) push_add(1,1,n,w);
    else if(inson(x,rt)){
        int p=wson(x,rt);
        push_add(1,1,first[p]-1,w);
        push_add(1,second[p]+1,n,w);
    }
    else push_add(1,first[x],second[x],w);
}
int find(int x){
    while(c[x][0]) down(x),x=c[x][0];
    return x;
}
void acs(int x){
    int y=0;
    while(x){
        splay(x);
        if(c[x][1]) add(find(c[x][1]),1);
        if(y) add(find(y),-1);
        c[x][1]=y; y=x; x=fa[x];
    }
}
double addup(int x){
    if(x==rt) return (double)push_ans(1,1,n)/n;
    if(inson(x,rt)){
        int p=wson(x,rt);
        return ((double)push_ans(1,1,first[p]-1)+(double)push_ans(1,second[p]+1,n))/(n-(second[p]-first[p]+1));
    }
    else return (double)push_ans(1,first[x],second[x])/(second[x]-first[x]+1);
}
void mrt(int x){splay(x); rt=x; swap(c[x][0],c[x][1]); rev[x]^=1;}
int main()
{
    int x,y;
    n=read(); m=read();
    for(int i=1;i<n;i++) x=read(),y=read(),insert(x,y);
    rt=1; build(1,1,n); dfs(1,0);
    char ch[15]; 
    for(int i=1;i<=m;i++){
        scanf("%s",ch); x=read();
        if(ch[2]=='Q') printf("%.10lf\n",addup(x));
        else{
            acs(x);
            if(ch[2]=='C') mrt(x);
        }
    }
    return 0;
}
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posted @ 2017-06-23 23:46  友人Aqwq  阅读(171)  评论(0编辑  收藏  举报