[BZOJ4034][HAOI2015]T2 做题笔记

·· / ·– ·· ·-·· ·-·· / ·–· · ·-· ··· ·· ··· - / ··- -· - ·· ·-·· / ·· / ·– ·· -·

题目来源：http://www.lydsy.com/JudgeOnline/problem.php?id=4034

[BZOJ4196][NOI2015]软件包管理器的既视感。。

这题是树链剖分+dfs序比较裸的题目，唯一需要注意的就是要开long long

#include <cstdio>
#include <algorithm>
#define lch now<<1
#define rch now<<1|1
const int N=200000;
typedef long long ll;
using namespace std;
ll C
;
int size
,son
,fa
,dep
;
int w
,ed
,top
,id[N<<2],cnt=0;
int ver[N<<1],nxt[N<<1],head
,tot=1;
int n,m;
struct Tree {
ll sum,del;
}I[N<<2];
void add (int u,int v) {
ver[++tot]=v;nxt[tot]=head[u];head[u]=tot;
}
void dfs_1 (int u,int from) {
int v;size[u]=1;son[u]=0;fa[u]=from;
for (int i=head[u];i;i=nxt[i]) {
v=ver[i];
if (v==fa[u]) continue;
dep[v]=dep[u]+1;
dfs_1(v,u); size[u]+=size[v];
if (!son[u]||size[son[u]]<size[v]) son[u]=v;
}
}
void dfs_2 (int u,int st) {
int v;w[u]=++cnt;top[u]=st;id[cnt]=u;
if (son[u]) dfs_2(son[u],st);
for (int i=head[u];i;i=nxt[i]) {
v=ver[i];
if (v==son[u]||v==fa[u]) continue;
dfs_2(v,v);
}
ed[u]=cnt;
}
inline void pushup (int now) {
I[now].sum=I[lch].sum+I[rch].sum;
}
inline void pushdown (int now,int l,int r) {
if (I[now].del!=0) {
int mid=(l+r)>>1;
I[lch].del+=I[now].del;I[rch].del+=I[now].del;
I[lch].sum+=I[now].del*(mid-l+1); I[rch].sum+=I[now].del*(r-mid);
I[now].del=0;
}
}
void build (int now,int l,int r) {
if (l==r) {
I[now].sum=C[id[l]];
I[now].del=0;
return ;
}
int mid=(l+r)>>1;
build(lch,l,mid); build(rch,mid+1,r);
pushup(now);
}
void change (int now,int l,int r,int x,int y,ll del) {
if (x<=l&&r<=y) {
I[now].del+=del;
I[now].sum+=del*(r-l+1);
return ;
}
int mid=(l+r)>>1;
pushdown(now,l,r);
if (x<=mid) change(lch,l,mid,x,y,del);
if (y>mid) change(rch,mid+1,r,x,y,del);
pushup(now);
}
ll query (int now,int l,int r,int x,int y) {
if (x<=l&&r<=y) return I[now].sum;
int mid=(l+r)>>1;ll ans=0;
pushdown(now,l,r);
if (x<=mid) ans+=query(lch,l,mid,x,y);
if (y>mid) ans+=query(rch,mid+1,r,x,y);
return ans;
}
ll getans (int x,int y) {
ll ans=0;
while (top[x]!=top[y]) {
ans+=query(1,1,n,w[top[x]],w[x]);
x=fa[top[x]];
}
ans+=query(1,1,n,w[y],w[x]);
return ans;
}
int main () {
int u,v,opt,x,y;
scanf("%d%d",&n,&m);
for (int i=1;i<=n;i++) scanf("%lld",&C[i]);
for (int i=1;i<n;i++) {
scanf("%d%d",&u,&v);
add(u,v); add(v,u);
}
dfs_1(1,0); dfs_2(1,1);
build(1,1,n);
for (int i=1;i<=m;i++) {
scanf("%d",&opt);
if (opt==1) {
scanf("%d%d",&x,&y);
change(1,1,n,w[x],w[x],y);
}
else if (opt==2) {
scanf("%d%d",&x,&y);
change(1,1,n,w[x],ed[x],y);
}
else if (opt==3) {
scanf("%d",&x);
printf("%lld\n",getans(x,1));
}
}
return 0;
}