1036: [ZJOI2008]树的统计Count

树链剖分 模板题：

   和线段树一起写各种bug:

#include<stdio.h>
#include<algorithm>
#include<math.h>
#include<vector>
#include<string.h>
#include<string>
#include<set>
#include<iostream>
using namespace std;
typedef long long ll;
#define N 33333

int head[N],top[N],fa[N],tot;

int son[N],p[N],fp[N],dep[N],pos;
int sz[N];

void init()
{
    tot=0;
    memset(head,-1,sizeof(head));
    memset(son,-1,sizeof(son));
    pos=0;
}

struct node
{
    int v,next;
}e[N<<1];

void add(int u,int v)
{
    e[tot].v=v;
    e[tot].next=head[u];
    head[u]=tot++;
}

void dfs(int u,int f,int d)
{
    dep[u]=d;
    fa[u]=f;
    sz[u]=1;

    for (int i=head[u];i!=-1;i=e[i].next)
    {
        int v=e[i].v;
        if (v==f) continue;
        dfs(v,u,d+1);
        sz[u]+=sz[v];
        if (son[u]==1||sz[son[u]]<sz[v]) son[u]=v;
    }
}

void getpos(int u,int sp)
{
    top[u]=sp;
    p[u]=++pos;
    fp[pos]=u;
    if (son[u]==-1) return;
    getpos(son[u],sp);
    for (int i=head[u];i!=-1;i=e[i].next)
    {
       int v=e[i].v;
       if (v!=son[u]&&v!=fa[u])
       getpos(v,v);
    }
}

struct node2
{
    int l,r,Max,sum;
}tree[N<<2];


void pushup(int rt)
{
    tree[rt].Max=max(tree[rt<<1].Max,tree[rt<<1|1].Max);
    tree[rt].sum=tree[rt<<1].sum+tree[rt<<1|1].sum;
}


void build(int l,int r,int rt)
{
    tree[rt].l=l;
    tree[rt].r=r;
    tree[rt].Max=tree[rt].sum=0;

    if (l==r) return ;
    int m=(l+r)>>1;
    build(l,m,rt<<1);
    build(m+1,r,rt<<1|1);
}

void update(int pos,int x,int l,int r,int rt)
{
    if (l==r)
    {
        tree[rt].Max=tree[rt].sum=x;
        return;
    }
    int m=(l+r)>>1;
    if (pos<=m) update(pos,x,l,m,rt<<1);
    else update(pos,x,m+1,r,rt<<1|1);
    pushup(rt);
}

int  querymax(int l,int r,int rt)
{
  if (tree[rt].l>=l&&tree[rt].r<=r)
      return tree[rt].Max;
  int m=(tree[rt].l+tree[rt].r)>>1;

  if (r<=m) return querymax(l,r,rt<<1);
  else if (l>m) return querymax(l,r,rt<<1|1);
  else return max(querymax(l,m,rt<<1),querymax(m+1,r,rt<<1|1));
}


int  querysum(int l,int r,int rt)
{
  if (tree[rt].l>=l&&tree[rt].r<=r)
      return tree[rt].sum;

  int m=(tree[rt].l+tree[rt].r)>>1;
  if (r<=m) return querysum(l,r,rt<<1);
  else if (l>m) return querysum(l,r,rt<<1|1);
  else return querysum(l,m,rt<<1)+querysum(m+1,r,rt<<1|1);
}

int Sum,Max;

void  lca(int u,int v)
{
    int fu=top[u];
    int fv=top[v];
    Sum=0;
    Max=-24242554;
    while (fu!=fv)
    {
        if (dep[fu]<dep[fv])
        {
            swap(fu,fv);
            swap(u,v);
        }

        Max=max(Max,querymax(p[fu],p[u],1));
        Sum+=querysum(p[fu],p[u],1);
        u=fa[fu];
        fu=top[u];
    }
    
    if (dep[u]>dep[v]) swap(u,v);
    Max=max(Max,querymax(p[u],p[v],1));
    Sum+=querysum(p[u],p[v],1);
    
    //Max=max(Max,querymax(p[fa[u]],p[v],1));
    //Sum+=querysum(p[fa[u]],p[v],1);
}
int a[N];

int main()
{
    int n;
    scanf("%d",&n);
    init();
    for (int i=1;i<n;i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        add(x,y);
        add(y,x);
    }
    dfs(1,0,0);
    getpos(1,1);
    build(1,pos,1);

    for (int i=1;i<=n;i++) scanf("%d",&a[i]),update(p[i],a[i],1,pos,1);

    int Q;
    scanf("%d",&Q);
    while (Q--)
    {
      char s[10];
      int x,y;
      scanf("%s",s);
      scanf("%d%d",&x,&y);
      if (s[0]=='C') update(p[x],y,1,pos,1);
      else
      {
          lca(x,y);
          if (s[1]=='M') printf("%d\n",Max);
          else printf("%d\n",Sum);
      }
    }

    return 0;
}