【hdu3966】Aragorn's Story

题意：给一棵树，并给定各个点权的值，然后有3种操作：
I C1 C2 K: 把C1与C2的路径上的所有点权值加上K
D C1 C2 K：把C1与C2的路径上的所有点权值减去K
Q C：查询节点编号为C的权值 

裸裸的树剖

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;

typedef long long LL;

#define N 50010

struct Node
{
    int to,next;
}e[N<<1];

int id,cnt;
int head[N];
int num[N],siz[N],top[N],son[N];
int dep[N],pos[N],rank1[N],fa[N];

LL sum[N<<2],add[N<<2];

char s[5];

int n,m,q;
int u,v;
int al,ar,ask;

inline void init()
{
    memset(son,-1,sizeof(son));
    memset(head,-1,sizeof(head));
id=0;
cnt=0;
}

void link(int x,int y)
{
    e[++cnt]=(Node){y,head[x]};
    head[x]=cnt;
}
 
void dfs(int x,int father,int d)
{
    siz[x]=1;
    dep[x]=d;
    fa[x]=father;
    for (int i=head[x];~i;i=e[i].next)
    {
        int t=e[i].to;
        if (t!=fa[x])
        {
            dfs(t,x,d+1);
            siz[x]+=siz[t];
            if (son[x]==-1 || siz[x]>siz[son[x]])
                son[x]=t;
        }
    }
}
 
void dfs2(int x,int cha)
{
    top[x]=cha;
    pos[x]=++id;
    rank1[pos[x]]=x;
    if (son[x]==-1)
        return ;    
    dfs2(son[x],cha);
    for(int i=head[x];~i;i=e[i].next)
    {
        int t=e[i].to;
        if(t!=son[x] && t!=fa[x])
            dfs2(t,t);
    }
}

void pushup(int now)
{
    sum[now]=max(sum[now<<1],sum[now<<1|1]);
}
 
void pushdown(int now,int m)
{
    if (add[now])
    {
        add[now<<1]+=add[now];
        add[now<<1|1]+=add[now];
        sum[now<<1]+=add[now]*(m-(m>>1));
        sum[now<<1|1]+=add[now]*(m>>1);
        add[now]=0;
    }
}

void build(int nowl,int nowr,int now)
{
    add[now]=0;
    if (nowl==nowr)
    {
        sum[now]=num[rank1[nowl]];
        return ;
    }
    int mid=(nowl+nowr)>>1;
    build(nowl,mid,now<<1);
    build(mid+1,nowr,now<<1|1);
    pushup(now);
}

void update(int nowl,int nowr,int now,int L,int R,int d)
{
    if (nowl>=L && nowr<=R)
    {
        add[now]+=d;
        sum[now]+=d*(nowr-nowl+1);
        return ;
    }
    pushdown(now,nowr-nowl+1);
    int mid=nowl+nowr>>1;
    if (L<=mid) update(nowl,mid,now<<1,L,R,d);
    if (mid<R) update(mid+1,nowr,now<<1|1,L,R,d);
    pushup(now);
}

int query(int nowl,int nowr,int now,int d)
{
    int res(0);
    if (nowl==nowr)
        return sum[now];
    pushdown(now,nowr-nowl+1);
    int mid=nowl+nowr>>1;
    if (d<=mid) res=query(nowl,mid,now<<1,d);
    else res=query(mid+1,nowr,now<<1|1,d);
    pushup(now);
    return res;
}

void work(int x,int y,int val)
{
    while (top[x]!=top[y])
    {
        if (dep[top[x]]<dep[top[y]])
            swap(x,y);
        update(1,n,1,pos[top[x]],pos[x],val);
        x=fa[top[x]];
    }
    if (dep[x]>dep[y])
        swap(x,y);
    update(1,n,1,pos[x],pos[y],val);
}
int main()
{
    while (scanf("%d%d%d",&n,&m,&q)!=EOF && n+m+q)
    {
        init();
        for (int i=1;i<=n;i++)
            scanf("%d",&num[i]);
        for (int i=1;i<=m;i++)
        {
            scanf("%d%d",&u,&v);
            link(u,v);
            link(v,u);
        }
        dfs(1,0,0);
        dfs2(1,1);
        build(1,n,1);
        while (q--)
        {
            scanf("%s",s);
            if (s[0]=='I')
            {
                scanf("%d%d%d",&al,&ar,&ask);
                work(al,ar,ask);
            }
            else if (s[0]=='D')
            {
                scanf("%d%d%d",&al,&ar,&ask);
                work(al,ar,-ask);
            }
            else
            {
                scanf("%d",&ask);
                printf("%d
",query(1,n,1,pos[ask]));
            }
        }
    }
    return 0;
}