bzoj1103: [POI2007]大都市meg

dfs序+树状数组维护；

#include<cstdio>#include<algorithm>#define rep(i,k,n) for(int i=k;i<=(n);i++)using namespace std;int read(){    int x=0;char ch=getchar();    while(ch<'0'||ch>'9')ch=getchar();    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}    return x;}const int N=250005;struct E{    int to,next;E(int to=0,int next=0):to(to),next(next){}}edge[2*N];int head[N],tot=0,n,l[N],r[N],m,tr[2*N],sta[2*N],top=0,cc[N],clock=0;void add(int x,int y){    edge[++tot]=E(y,head[x]);head[x]=tot;     edge[++tot]=E(x,head[y]);head[y]=tot;  }void Add(int x,int d){for(;x<=clock;x+=(x&-x))tr[x]+=d;}int Q(int x){int res=0;for(;x;x-=(x&-x))res+=tr[x];return res;}void dfs(){    sta[++top]=1;    while(top){        int u=sta[top];if(!l[u])l[u]=++clock;        for(int i=head[u];i;i=edge[i].next){            int v=edge[i].to;            if(!l[v]){                sta[++top]=v;break;            }        }if(sta[top]==u){        top--;r[u]=++clock;    }    }}int main(){//freopen("in.in","r",stdin);    n=read();int x,y;    rep(i,1,n-1){        x=read();y=read();add(x,y);    }dfs();    rep(i,2,n)Add(l[i],1),Add(r[i],-1);    m=read();char s[20];    rep(i,1,n+m-1){        scanf("%s",s);        if(s[0]=='A'){            x=read(),y=read();            Add(l[y],-1),Add(r[y],1);        }        else{x=read();printf("%d\n",Q(l[x]));}        }    }