AC日记——苹果树 codevs 1228

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

struct T_tree {
    int l,r,dis;
};
struct T_tree tree[400001];

struct T_edge {
    int from,to,next;
};
struct T_edge edge[100001];

struct T_interval {
    int li,ri;
};
struct T_interval find_[100001];

int n,m,num_edge=0,head[100001],tot=0;

inline void edge_add(int from,int to)
{
    num_edge++;
    edge[num_edge].to=to;
    edge[num_edge].from=from;
    edge[num_edge].next=head[from];
    head[from]=num_edge;
}

void dfs(int now)
{
    tot++;
    find_[now].li=tot;
    for(int i=head[now];i;i=edge[i].next)
    {
        dfs(edge[i].to);
    }
    find_[now].ri=tot;
}

void tree_up(int now)
{
    tree[now].dis=tree[now<<1].dis+tree[now<<1|1].dis;
}

void tree_build(int now,int l,int r)
{
    tree[now].l=l,tree[now].r=r;
    if(l==r)
    {
        tree[now].dis=1;
        return ;
    }
    int mid=(l+r)>>1;
    tree_build(now<<1,l,mid);
    tree_build(now<<1|1,mid+1,r);
    tree_up(now);
    return ;
}

void tree_change(int now,int to)
{
    if(to==tree[now].l&&tree[now].r==to)
    {
        if(tree[now].dis) tree[now].dis=0;
        else tree[now].dis=1;
        return ;
    }
    int mid=(tree[now].l+tree[now].r)>>1;
    if(to>mid) tree_change(now<<1|1,to);
    else tree_change(now<<1,to);
    tree_up(now);
}

int tree_query(int now,int l,int r)
{
    if(tree[now].l==l&&tree[now].r==r)
    {
        return tree[now].dis;
    }
    int mid=(tree[now].l+tree[now].r)>>1;
    if(l>mid) return tree_query(now<<1|1,l,r);
    else if(r<=mid) return tree_query(now<<1,l,r);
    else return tree_query(now<<1,l,mid)+tree_query(now<<1|1,mid+1,r);
}

int main()
{
    scanf("%d",&n);
    int from,to;
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&from,&to);
        edge_add(from,to);
    }
    dfs(1);
    tree_build(1,1,n);
    scanf("%d",&m);
    char t_do;
    int to_ch;
    for(int i=1;i<=m;i++)
    {
        //scanf("%c %d",&t_do,&to_ch);
        //scanf("%c",&t_do);
        //scanf("%d",&to_ch);
        cin>>t_do>>to_ch;
        if(t_do==‘Q‘) printf("%d\n",tree_query(1,find_[to_ch].li,find_[to_ch].ri));
        else tree_change(1,find_[to_ch].li);
    }
    return 0;
}