樹鏈剖分模板 1036: [ZJOI2008]樹的統計Count

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
#define inf 0x7fffffff
#define N 30005 
#define M 60005
using namespace std;
int n,q,cnt,sz;
int v[N],dep[N],size[N],head[N],fa[N];
int pos[N],bl[N];
struct data{int to,next;}e[M];
struct seg{int l,r,mx,sum;}t[100005];
void insert(int u,int v)
{
    e[++cnt].to=v;e[cnt].next=head[u];head[u]=cnt;
    e[++cnt].to=u;e[cnt].next=head[v];head[v]=cnt;
}
void ini()
{
    scanf("%d",&n);
    for(int i=1;i<n;i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        insert(x,y);
    }
    for(int i=1;i<=n;i++)scanf("%d",&v[i]);
}
void dfs1(int x)
{
    size[x]=1;
    for(int i=head[x];i;i=e[i].next)
    {
        if(e[i].to==fa[x])continue;
        dep[e[i].to]=dep[x]+1;
        fa[e[i].to]=x;
        dfs1(e[i].to);
        size[x]+=size[e[i].to];
    }
}
void dfs2(int x,int chain)
{
    int k=0;sz++;
    pos[x]=sz;//??x??????????
    bl[x]=chain;
    for(int i=head[x];i;i=e[i].next)
        if(dep[e[i].to]>dep[x]&&size[e[i].to]>size[k])
            k=e[i].to;//?????????????
    if(k==0)return;
    dfs2(k,chain);
    for(int i=head[x];i;i=e[i].next)
        if(dep[e[i].to]>dep[x]&&k!=e[i].to)
            dfs2(e[i].to,e[i].to);//????????
}
void build(int k,int l,int r)//????
{
    t[k].l=l;t[k].r=r;
    if(l==r)return;
    int mid=(l+r)>>1;
    build(k<<1,l,mid);
    build(k<<1|1,mid+1,r);
}
void change(int k,int x,int y)//???????
{
    int l=t[k].l,r=t[k].r,mid=(l+r)>>1;
    if(l==r){t[k].sum=t[k].mx=y;return;}
    if(x<=mid)change(k<<1,x,y);
    else change(k<<1|1,x,y);
    t[k].sum=t[k<<1].sum+t[k<<1|1].sum;
    t[k].mx=max(t[k<<1].mx,t[k<<1|1].mx);
}
int querysum(int k,int x,int y)//???????
{
    int l=t[k].l,r=t[k].r,mid=(l+r)>>1;
    if(l==x&&y==r)return t[k].sum;
    if(y<=mid)return querysum(k<<1,x,y);
    else if(x>mid)return querysum(k<<1|1,x,y);
    else {return querysum(k<<1,x,mid)+querysum(k<<1|1,mid+1,y);}
}
int querymx(int k,int x,int y)//?????????
{

    int l=t[k].l,r=t[k].r,mid=(l+r)>>1;
    if(l==x&&y==r)return t[k].mx;
    if(y<=mid)return querymx(k<<1,x,y);
    else if(x>mid)return querymx(k<<1|1,x,y);
    else {return max(querymx(k<<1,x,mid),querymx(k<<1|1,mid+1,y));}
}
int solvesum(int x,int y)
{
    int sum=0;
    while(bl[x]!=bl[y])
    {
        if(dep[bl[x]]<dep[bl[y]])swap(x,y);
        sum+=querysum(1,pos[bl[x]],pos[x]);
        x=fa[bl[x]];
    }
    if(pos[x]>pos[y])swap(x,y);
    sum+=querysum(1,pos[x],pos[y]);
    return sum;
}
int solvemx(int x,int y)
{
    int mx=-inf;
    while(bl[x]!=bl[y])
    {
        if(dep[bl[x]]<dep[bl[y]])swap(x,y);
        mx=max(mx,querymx(1,pos[bl[x]],pos[x]));
        x=fa[bl[x]];
    }
    if(pos[x]>pos[y])swap(x,y);
    mx=max(mx,querymx(1,pos[x],pos[y]));
    return mx;
}
void solve()
{
    build(1,1,n);
    for(int i=1;i<=n;i++)
        change(1,pos[i],v[i]);
    scanf("%d",&q);
    char ch[10];
    for(int i=1;i<=q;i++) 
    {
        int x,y;scanf("%s%d%d",ch,&x,&y);
        if(ch[0]=='C'){v[x]=y;change(1,pos[x],y);}
        else
        {
            if(ch[1]=='M')
               printf("%d\n",solvemx(x,y));
            else
                printf("%d\n",solvesum(x,y));
        }
    }
}
int main()
{
        freopen("data.txt","r",stdin);
    freopen("Ac.txt","w",stdout);
    ini();
    dfs1(1);
    dfs2(1,1);
    solve();
    return 0;
}