Code:
#include
#define maxn 300002
#define ll long long
using namespace std;
void setIO(string s)
{
string in=s+".in";
string out=s+".out";
freopen(in.c_str(),"r",stdin);
freopen(out.c_str(),"w",stdout);
}
namespace tr
{
#define lson t[x].l
#define rson t[x].r
#define mid ((l+r)>>1)
int cnt;
int newnode(){ return ++cnt; }
struct Node
{
int l,r;
ll val, sumv;
}t[maxn*60];
void insert(int &x,int l,int r,int k,ll delta)
{
if(!x) x = newnode();
t[x].sumv += delta;
if(l==r) { t[x].val=delta; return; }
if(k <= mid) insert(lson, l, mid, k, delta);
else insert(rson, mid + 1, r, k, delta);
}
int merge(int u,int v)
{
if(!u||!v) return u + v;
int x = newnode();
t[x].sumv = t[u].sumv + t[v].sumv;
lson = merge(t[u].l,t[v].l);
rson = merge(t[u].r,t[v].r);
return x;
}
ll query(int x,int l,int r,int L,int R)
{
if(!x) return 0;
if(l>=L&&r<=R) return t[x].sumv;
ll tmp=0;
if(L<=mid) tmp+=query(lson,l,mid,L,R);
if(R>mid) tmp+=query(rson,mid+1,r,L,R);
return tmp;
}
};
int n,Q,edges;
int hd[maxn],to[maxn<<1],nex[maxn<<1],fa[maxn],siz[maxn],dep[maxn],rt[maxn];
void add(int u,int v)
{
nex[++edges]=hd[u],hd[u]=edges,to[edges]=v;
}
void get(int u,int ff)
{
int i,v;
siz[u]=1, dep[u] = dep[ff] + 1;
for(i=hd[u];i;i=nex[i])
{
v=to[i];
if(v==ff) continue;
get(v,u), siz[u]+=siz[v];
}
}
void DFS(int u,int ff)
{
int i,v;
tr::insert(rt[u],0,n,dep[u],1ll*(siz[u]-1));
for(i=hd[u];i;i=nex[i])
{
v=to[i];
if(v==ff) continue;
DFS(v, u);
rt[u] = tr::merge(rt[v], rt[u]);
}
}
int main()
{
// setIO("input");
int i,j,x,y;
ll ans=0;
scanf("%d%d",&n,&Q);
for(i=1;i