luoguP2590 [ZJOI2008]树的统计(树链剖分)

Posted 2020-11-09 eternal风度

luogu P2590 [ZJOI2008]树的统计 题目

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<iomanip>
#include<algorithm>
#include<ctime>
#include<queue>
#define rg register
#define lst long long
#define N 30050
#define ls (now<<1)
#define rs (now<<1|1)
using namespace std;

int n,Q,cnt,ss,root,ans;
struct EDGE{
    int to,nxt;
}edge[N<<1];
struct TREE{
    int l,r,Max,sum;
}ljl[N<<2];
int v[N],head[N];
int fa[N],deep[N],size[N],num[N];
int vv[N],top[N],son[N];

inline void add(rg int p,rg int q){edge[++cnt]=(EDGE){q,head[p]};head[p]=cnt;}
inline int read()
{
    rg int s=0,m=1;rg char ch=getchar();
    while(ch!=‘-‘&&(ch<‘0‘||ch>‘9‘))ch=getchar();
    if(ch==‘-‘)m=-1,ch=getchar();
    while(ch>=‘0‘&&ch<=‘9‘)s=(s<<3)+(s<<1)+ch-‘0‘,ch=getchar();
    return s*m;
}

inline void init()
{
    n=read();root=1;
    for(rg int i=1;i<n;++i)
    {
        rg int p=read(),q=read();
        add(p,q),add(q,p);
    }
    for(rg int i=1;i<=n;++i)v[i]=read();
}

void dfs_1(rg int now,rg int fm,rg int dep)
{
    rg int kk=0;
    fa[now]=fm,deep[now]=dep,size[now]=1;
    for(rg int i=head[now];i;i=edge[i].nxt)
    {
        rg int qw=edge[i].to;
        if(qw!=fm)
        {
            dfs_1(qw,now,dep+1);
            size[now]+=size[qw];
            if(size[qw]>kk)kk=size[qw],son[now]=qw;
        }
    }
}

void dfs_2(rg int now,rg int up)
{
    num[now]=++ss,vv[ss]=v[now],top[now]=up;
    if(son[now])dfs_2(son[now],top[now]);
    for(rg int i=head[now];i;i=edge[i].nxt)
    {
        rg int qw=edge[i].to;
        if(qw!=fa[now]&&qw!=son[now])
            dfs_2(qw,qw);
    }
}

inline void Pushup(rg int now)
{
    ljl[now].Max=max(ljl[ls].Max,ljl[rs].Max);
    ljl[now].sum=ljl[ls].sum+ljl[rs].sum;
}

void build(rg int now,rg int ll,rg int rr)
{
    ljl[now]=(TREE){ll,rr};
    if(ll==rr)
    {
        ljl[now].Max=ljl[now].sum=vv[ll];
        return;
    }
    rg int mid=(ll+rr)>>1;
    build(ls,ll,mid),build(rs,mid+1,rr);
    Pushup(now);
}

void change(rg int now,rg int kk,rg int x)
{
    if(ljl[now].l==kk&&ljl[now].r==kk)
    {
        ljl[now].Max=ljl[now].sum=x;
        return;
    }
    rg int mid=(ljl[now].l+ljl[now].r)>>1;
    if(kk<=mid)change(ls,kk,x);
    else change(rs,kk,x);
    Pushup(now);
}

int get_max(rg int now,rg int ll,rg int rr)
{
    rg int ss=-1e9;
    if(ljl[now].l>=ll&&ljl[now].r<=rr)return ljl[now].Max;
    rg int mid=(ljl[now].l+ljl[now].r)>>1;
    if(rr<=mid)ss=max(ss,get_max(ls,ll,rr));
    if(ll>mid) ss=max(ss,get_max(rs,ll,rr));
    if(ll<=mid&&rr>mid)ss=max(ss,max(get_max(ls,ll,mid),get_max(rs,mid+1,rr)));
    return ss;
}

int get_sum(rg int now,rg int ll,rg int rr)
{
    rg int ss=0;
    if(ljl[now].l>=ll&&ljl[now].r<=rr)return ljl[now].sum;
    rg int mid=(ljl[now].l+ljl[now].r)>>1;
    if(rr<=mid)ss+=get_sum(ls,ll,rr);
    if(ll>mid) ss+=get_sum(rs,ll,rr);
    if(ll<=mid&&rr>mid)ss+=get_sum(ls,ll,mid)+get_sum(rs,mid+1,rr);
    return ss;
}

inline void work(rg int x,rg int y,rg int op)
{
    if(num[x]>num[y])swap(x,y);
    if(!op)ans=max(ans,get_max(1,num[x],num[y]));
    if(op) ans+=get_sum(1,num[x],num[y]);
}

inline void Work(rg int x,rg int y,rg int op)
{
    while(top[x]!=top[y])
    {
        if(deep[top[x]]<deep[top[y]])swap(x,y);
        work(top[x],x,op);
        x=fa[top[x]];
    }
    work(x,y,op);
}

inline void Ans()
{
    Q=read();
    for(rg int i=1;i<=Q;++i)
    {
        char type[6];cin>>type;
        rg int x=read(),y=read();
        if(type[3]==‘N‘){         change(1,num[x],y);}//change
        if(type[3]==‘X‘){ans=-1e9;Work(x,y,0);printf("%d\n",ans);}//qmax
        if(type[3]==‘M‘){ans=0;   Work(x,y,1);printf("%d\n",ans);}//qsum
    }
}

int main()
{
    init();
    dfs_1(root,0,0);
    dfs_2(root,root);
    build(1,1,n);
    Ans();
    return 0;
}