[jzoj1016][poj3321]苹果树（dfs序+树状数组维护）

#include<cstdio>
#include<cstring>
#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstdlib>
#define ll long long
using namespace std;
inline int read(){
int x=0;char ch=' ';int f=1;
while(ch!='-'&&(ch<'0'||ch>'9'))ch=getchar();
if(ch=='-')f=-1,ch=getchar();
while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
return x*f;
}
struct edge{
int to,next;
}e[200001];
int n,m,tot;
int head[100001];
inline void addedge(int x,int y){
e[++tot].to=y;e[tot].next=head[x];head[x]=tot;
}
int dfn[100001];
int mp[100001];
int v[100001];
int t[100001];
int size[100001];
void dfs(int x,int fa){
dfn[++tot]=x;
mp[x]=tot;
size[x]=1;
for(int i=head[x];i;i=e[i].next){
int u=e[i].to;
if(u==fa)continue;
dfs(u,x);
size[x]+=size[u];
}
}
inline int lowbit(int x){
return x&-x;
}
inline void update(int x){
int cg;
if(v[x])cg=-1;
else cg=1;
v[x]+=cg;
while(x<=n){
t[x]+=cg;
x+=lowbit(x);
}
}
inline int query(int x){
int sum=0;
while(x){
sum+=t[x];
x-=lowbit(x);
}
return sum;
}
int main(){
n=read();
for(int i=1;i<n;i++){
int x=read(),y=read();
addedge(x,y);addedge(y,x);
}
tot=0;
dfs(1,0);
for(int i=1;i<=n;i++){
update(i);
}
m=read();
for(int i=1;i<=m;i++){
char ch[3];
scanf("%s",ch);
int x=read();
if(ch[0]=='C'){
update(mp[x]);
}
else{
printf("%d\n",query(mp[x]+size[x]-1)-query(mp[x]-1));
}
}
return 0;
}