hdu3966 Aragorn's Story（树链剖分）

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define ll long long
#define inf 0x3f3f3f3f
#define N 50010
inline int read(){
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-') f=-1;ch=getchar();}
while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();
return x*f;
}
int n,m,q,a
,w
,h
,num=0,fa
,dep
,son
,size
,top
,id
,dfn=0;
struct edge{
int to,next;
}data[N<<1];
struct node{
int add,x;
}tree[N<<2];
void dfs1(int x){
size[x]=1;
for(int i=h[x];i;i=data[i].next){
int y=data[i].to;
if(fa[x]==y) continue;
fa[y]=x;dep[y]=dep[x]+1;dfs1(y);size[x]+=size[y];
if(size[y]>size[son[x]]) son[x]=y;
}
}
void dfs2(int x,int tp){
id[x]=++dfn;top[x]=tp;w[dfn]=a[x];
if(son[x]) dfs2(son[x],tp);
for(int i=h[x];i;i=data[i].next){
int y=data[i].to;
if(y==fa[x]||y==son[x]) continue;
dfs2(y,y);
}
}
void build(int p,int l,int r){
tree[p].add=0;
if(l==r){tree[p].x=w[l];return;}
int mid=l+r>>1;
build(p<<1,l,mid);build(p<<1|1,mid+1,r);
}
void pushdown(int p){
if(!tree[p].add) return;
tree[p<<1].add+=tree[p].add;tree[p<<1|1].add+=tree[p].add;
tree[p<<1].x+=tree[p].add;tree[p<<1|1].x+=tree[p].add;
tree[p].add=0;
}
void add1(int p,int l,int r,int x,int y,int val){
if(x<=l&&r<=y){tree[p].add+=val;tree[p].x+=val;return;}
int mid=l+r>>1;pushdown(p);
if(x<=mid) add1(p<<1,l,mid,x,y,val);
if(y>mid) add1(p<<1|1,mid+1,r,x,y,val);
}
int query(int p,int l,int r,int x){
if(l==r) return tree[p].x;
int mid=l+r>>1;pushdown(p);
if(x<=mid) return query(p<<1,l,mid,x);
else return query(p<<1|1,mid+1,r,x);
}
void doadd(int x,int y,int val){
while(top[x]!=top[y]){
if(dep[top[x]]<dep[top[y]]) swap(x,y);
add1(1,1,n,id[top[x]],id[x],val);
x=fa[top[x]];
}
if(id[x]>id[y]) swap(x,y);
add1(1,1,n,id[x],id[y],val);
}
int main(){
//  freopen("a.in","r",stdin);
while(~scanf("%d%d%d",&n,&m,&q)){
memset(h,0,sizeof(h));memset(fa,0,sizeof(fa));
memset(son,0,sizeof(son));num=dfn=0;
for(int i=1;i<=n;++i) a[i]=read();
for(int i=1;i<n;++i){
int x=read(),y=read();
data[++num].to=y;data[num].next=h[x];h[x]=num;
data[++num].to=x;data[num].next=h[y];h[y]=num;
}
dep[1]=1;dfs1(1);dfs2(1,1);build(1,1,n);
while(q--){
char op[1];scanf("%s",op);int x=read();
if(op[0]=='I'){int y=read(),val=read();doadd(x,y,val);}
if(op[0]=='D'){int y=read(),val=read();doadd(x,y,-val);}
if(op[0]=='Q') printf("%d\n",query(1,1,n,id[x]));
}
}
return 0;
}