HDU3966(树链剖分)

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <iostream>
#include <string.h>
#include <algorithm>
#include <stdio.h>
#include <vector>

using namespace std;
const int N=50010;

int n,m,Q;
int tim;

int num
,siz
,top
,son
;
int dep
,tid
,rank
,fa
;
int head
,to[2*N],next[2*N],edge;

void Init()
{
memset(head,-1,sizeof(head));
memset(son,-1,sizeof(son));
tim=0;
edge=0;
}

void addedge(int u,int v)
{
to[edge]=v,next[edge]=head[u],head[u]=edge++;
to[edge]=u,next[edge]=head[v],head[v]=edge++;
}

//树链剖分部分
void dfs1(int u,int father,int d)
{
dep[u]=d;
fa[u]=father;
siz[u]=1;
for(int i=head[u];~i;i=next[i])
{
int v=to[i];
if(v!=father)
{
dfs1(v,u,d+1);
siz[u]+=siz[v];
if(son[u]==-1||siz[v]>siz[son[u]])
son[u]=v;
}
}
}

void dfs2(int u,int tp)
{
top[u]=tp;
tid[u]=++tim;
rank[tid[u]]=u;
if(son[u]==-1) return;
dfs2(son[u],tp);
for(int i=head[u];~i;i=next[i])
{
int v=to[i];
if(v!=son[u]&&v!=fa[u])
dfs2(v,v);
}
}

//线段树部分
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1

int sum[4*N],col[4*N];

void PushUP(int rt)
{
sum[rt]=max(sum[rt<<1],sum[rt<<1|1]);
}

void PushDown(int rt,int m)
{
if(col[rt])
{
col[rt<<1]+=col[rt];
col[rt<<1|1]+=col[rt];
sum[rt<<1]+=(m-(m>>1))*col[rt];
sum[rt<<1|1]+=(m>>1)*col[rt];
col[rt]=0;
}
}

void Build(int l,int r,int rt)
{
col[rt]=0;
if(l==r)
{
sum[rt]=num[rank[l]];
return;
}
int mid=(l+r)>>1;
Build(lson);
Build(rson);
PushUP(rt);
}

void Update(int L,int R,int v,int l,int r,int rt)
{
if(L<=l&&R>=r)
{
col[rt]+=v;
sum[rt]+=v*(r-l+1);
return;
}
PushDown(rt,r-l+1);
int mid=(l+r)>>1;
if(L<=mid)
Update(L,R,v,lson);
if(R>mid)
Update(L,R,v,rson);
PushUP(rt);
}

int Query(int l,int r,int rt,int val)
{
if(l==r)
return sum[rt];
PushDown(rt,r-l+1);
int mid=(l+r)>>1;
int ret=0;
if(val<=mid) ret=Query(lson,val);
else         ret=Query(rson,val);
PushUP(rt);
return ret;
}

void Change(int x,int y,int val)
{
while(top[x]!=top[y])
{
if(dep[top[x]]<dep[top[y]]) swap(x,y);
Update(tid[top[x]],tid[x],val,1,n,1);
x=fa[top[x]];
}
if(dep[x]>dep[y]) swap(x,y);
Update(tid[x],tid[y],val,1,n,1);
}

int main()
{
char oper[5];
int a,b,c;
while(~scanf("%d%d%d",&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",&a,&b);
addedge(a,b);
}
dfs1(1,0,0);
dfs2(1,1);
Build(1,n,1);
while(Q--)
{
scanf("%s",oper);
if(oper[0]=='Q')
{
scanf("%d",&a);
printf("%d\n",Query(1,n,1,tid[a]));
}
else
{
scanf("%d%d%d",&a,&b,&c);
if(oper[0]=='D') c=-c;
Change(a,b,c);
}
}
}
return 0;
}