【SHOI2012】魔法树（树链剖分，线段树）

【SHOI2012】魔法树

题面

BZOJ上找不到这道题目

只有洛谷上有。。

所以粘贴洛谷的题面

题解

树链剖分之后直接维护线段树就可以了

树链剖分良心模板题

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
#define MAX 110000
#define lson (now<<1)
#define rson (now<<1|1)
#define ll long long
inline int read()
{
    register int x=0,t=1;
    register char ch=getchar();
    while((ch<'0'||ch>'9')&&ch!='-')ch=getchar();
    if(ch=='-'){t=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-48;ch=getchar();}
    return x*t;
}
struct Node
{
    long long s;
    long long ly;
}t[MAX<<2];
int tim;
struct Line
{
    int v,next;
}e[MAX];
int h[MAX],cnt=1;
int dfn[MAX],low[MAX],dep[MAX],ff[MAX],size[MAX],hson[MAX],top[MAX];
int line[MAX],N;
inline void Add(int u,int v)
{
    e[cnt]=(Line){v,h[u]};
    h[u]=cnt++;
}
void DFS1(int u)
{
    dep[u]=dep[ff[u]]+1;size[u]=1;
    for(int i=h[u];i;i=e[i].next)
    {
        int v=e[i].v;
        DFS1(v);
        if(size[v]>size[hson[u]])hson[u]=v;
        size[u]+=size[v];
    }
}
void DFS2(int u,int tp)
{
    top[u]=tp;dfn[u]=++tim;line[tim]=u;
    if(hson[u])DFS2(hson[u],tp);
    for(int i=h[u];i;i=e[i].next)
    {
        int v=e[i].v;
        if(v==hson[u])continue;
        DFS2(v,v);
    }
    low[u]=tim;
}
void pushup(int now)
{
    t[now].s=t[lson].s+t[rson].s;
}
void putlazy(int now,int ly,int l,int r)
{
    t[now].s+=1LL*(r-l+1)*ly;
    t[now].ly+=ly;
}
void pushdown(int now,int l,int r)
{
    int mid=(l+r)>>1;
    putlazy(lson,t[now].ly,l,mid);
    putlazy(rson,t[now].ly,mid+1,r);
    t[now].ly=0;
}
void Modify(int now,int l,int r,int al,int ar,int d)
{
    if(l==al&&r==ar){putlazy(now,d,l,r);return;}
    int mid=(l+r)>>1;
    t[now].s+=1LL*(ar-al+1)*d;
    if(ar<=mid)Modify(lson,l,mid,al,ar,d);
    else if(al>mid)Modify(rson,mid+1,r,al,ar,d);
    else {Modify(lson,l,mid,al,mid,d);Modify(rson,mid+1,r,mid+1,ar,d);}
}
ll Query(int now,int l,int r,int al,int ar)
{
    if(l==al&&r==ar)return t[now].s;
    int mid=(l+r)>>1;
    pushdown(now,l,r);
    ll re=0;
    if(ar<=mid)re=Query(lson,l,mid,al,ar);
    else if(al>mid)re=Query(rson,mid+1,r,al,ar);
    else re=Query(lson,l,mid,al,mid)+Query(rson,mid+1,r,mid+1,ar);
    pushup(now);
    return re;
}
void LCA(int u,int v,int d)
{
    while(top[u]!=top[v])
    {
        if(dep[top[u]]<dep[top[v]])swap(u,v);
        Modify(1,1,N,dfn[top[u]],dfn[u],d);
        u=ff[top[u]];
    }
    if(dep[v]>dep[u])swap(u,v);
    Modify(1,1,N,dfn[v],dfn[u],d);
}
int main()
{
    N=read();
    for(int i=1;i<N;++i)
    {
        int x=read()+1,y=read()+1;
        ff[y]=x;
        Add(x,y);
    }
    DFS1(1);DFS2(1,1);
    int Q=read();
    while(Q--)
    {
        char ch[3];scanf("%s",ch);
        if(ch[0]=='A')
        {
            int u=read()+1,v=read()+1,d=read();
            LCA(u,v,d);
        }
        else
        {
            int u=read()+1;
            printf("%lld\n",Query(1,1,N,dfn[u],low[u]));
        }
    }
    return 0;
}