[Split tree chain] [Fenwick tree] Luogu P3676 small fresh data structure that

Title Description

Long, long ago, there was a huge tree n points, each point has a right to the point.

There are q operations, each operation is to modify a point or a point designated the right point, when asked at this point to each of them the subtree rooted at the right point and the sum of squares.

(The title is not easy to understand, did not look too understand can see examples explain)

 

answer

• Grandpa blog ( poke me )

 

Code

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream> 
 4 #define ll long long
 5 #define sqr(x) (x)*(x)
 6 using namespace std;
 7 const ll N=2e5+10; 
 8 struct edge{ll from,to;}e[N<<1];
 9 ll n,m,cnt,ans,tot,w[N],c[N],fa[N],sz[N],id[N],pos[N],deep[N],son[N],top[N],head[N],sz1[N],sz2[N];
10 void add(ll x,ll y) { for (int i=x;i<=n;i+=i&(-i)) sz1[i]+=y,sz2[i]+=x*y; }
11 ll query(ll x) { ll r=0; for (ll i=x;i;i-=i&(-i)) r+=(x+1)*sz1[i]-sz2[i]; return r; }
12 void insert(ll x,ll y)
13 {
14     e[++cnt].to=y,e[cnt].from=head[x],head[x]=cnt;
15     e[++cnt].to=x,e[cnt].from=head[y],head[y]=cnt;
16 }
17 void dfs1(ll x)
18 {
19     deep[x]=deep[fa[x]]+1,sz[x]=1;
20     for (ll i=head[x];i;i=e[i].from) if (e[i].to!=fa[x])
21     {
22         fa[e[i].to]=x,dfs1(e[i].to),sz[x]+=sz[e[i].to],w[x]+=w[e[i].to];
23         if (sz[e[i].to]>sz[son[x]]) son[x]=e[i].to;
24     }
25     ans+=sqr(w[x]);
26 }
27 void dfs2(ll x,ll pre)
28 {
29     top[x]=pre;pos[id[x]=++tot]=x,add(id[x],w[x]-w[pos[tot-1]]);
30     if (son[x]) dfs2(son[x],pre);
31     for (ll i=head[x];i;i=e[i].from) if (fa[x]!=e[i].to&&e[i].to!=son[x]) dfs2(e[i].to,e[i].to);
32 }
33 void modify(ll x,ll y)
34 {
35     ll l=0,r=0;
36     for (;x;x=fa[top[x]]) l+=id[x]-id[top[x]]+1,r+=query(id[x])-query(id[top[x]]-1),add(id[top[x]],y),add(id[x]+1,-y);
37     ans+=y*(y*l+(r<<1));
38 }
39 ll calc(ll u)
40 {
41     ll k=0,x=query(1),s=0;
42     for (;u;u=fa[top[u]]) k+=id[u]-id[top[u]]+1,s+=query(id[u])-query(id[top[u]]-1);
43     return ans+x*((k+1)*x-(s<<1));
44 }
45 int main()
46 {
47     scanf("%lld%lld",&n,&m);
48     for (ll i=2,x,y;i<=n;i++) scanf("%lld%lld",&x,&y),insert(x,y);
49     for (ll i=1;i<=n;i++) scanf("%lld",&c[i]),w[i]=c[i];
50     dfs1(1),dfs2(1,1);
51     for (ll op,x,y;m;m--)
52     {
53         scanf("%lld%lld",&op,&x);
54         if (op==1) scanf("%lld",&y),y-=c[x],c[x]+=y,modify(x,y); else printf("%lld\n",calc(x));
55     }
56 }