#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fr first
#define sc second
const int mxn=5e5+5,M=1e9+7,kkk=(1<<21);
int n,q,r,st[mxn],fn[mxn],cnt=0,sz[mxn],g[mxn],bbb;
ll ans,fuck[mxn],rfuck[mxn];
vector<int>v[mxn];
ll ferma(ll x){
ll num=M-2,res=1;
while(num){
if(num&1)res=(res*x)%M;
x=(x*x)%M;
num/=2;
}
return res;
}
void dfs(int z){
sz[z]=1;
st[z]=++cnt;
for(auto i:v[z]){
if(!st[i]){
dfs(i);
sz[z]+=sz[i];
}
}
fn[z]=cnt;
}
void make(){
fuck[0]=rfuck[0]=1;
for(int i=1;i<=n+r;i++){
fuck[i]=(fuck[i-1]*i)%M;
rfuck[i]=ferma(fuck[i]);
}
}
ll comb(int x,int y,bool w){
if(x>y){
bbb+=(w)?-1:1;
return 1;
}
ll res=fuck[y]*rfuck[x];
res%=M;
res*=rfuck[y-x];
return res%M;
}
struct segment{
ll val[kkk];
void up(int id,int L,int R,int l,int x){
if(L+1==R){
val[id]=x;
return;
}
int mid=(L+R)/2;
if(l<mid)
up(id*2,L,mid,l,x);
else
up(id*2+1,mid,R,l,x);
val[id]=val[id*2]+val[id*2+1];
}
ll get(int id ,int L,int R,int l,int r){
if(L==l && R==r)
return val[id];
int mid=(L+R)/2;
ll res=0;
if(l<mid)
res+=get(id*2,L,mid,l,min(r,mid));
if(r>mid)
res+=get(id*2+1,mid,R,max(l,mid),r);
return res;
}
}seg[2];
struct fnd{
set<int>s[kkk];
int get(int id,int L,int R,int l,int r){
if(L==l && R==r)
return ((s[id].size())?*s[id].rbegin():0);
int mid=(L+R)/2,res=((s[id].size())?*s[id].rbegin():0),x=0;
if(l<mid){
x=get(id*2,L,mid,l,min(r,mid));
}
return (x)?x:res;
}
void add(int id ,int L,int R,int l,int r,int x,bool y){
if(l>=R)return 0;
if(L==l && R==r){
if(y)
s[id].insert(x);
else
s[id].erase(x);
return;
}
int mid=(L+R)/2;
if(l<mid)
add(id*2,L,mid,l,min(r,mid),x,y);
if(r>mid)
add(id*2+1,mid,R,max(l,mid),r,x,y);
}
}fnd;
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin>>n>>r;
for(int i=1;i<n;i++){
int x,y;
cin>>x>>y;
v[x].push_back(y);
v[y].push_back(x);
}
dfs(1);
make();
ans=comb(n-1,n+r-1,0);
seg[0].up(1,1,n+1,1,n);
seg[1].up(1,1,n+1,1,r);
fnd.add(1,1,n+1,1,n+1,1,1);
g[1]=r;
cout<<ans<<'\n';
cin>>q;
while(q--){
int ty,x,y,z;
cin>>ty;
if(ty==1){
cin>>x>>g[x];
z=fnd.get(1,1,n+1,st[x],fn[x]+1);
fnd.add(1,1,n+1,st[x],fn[x]+1,st[x],1);
}
else{
cin>>x;
fnd.add(1,1,n+1,st[x],st[y]+1,st[x],0);
z=fnd.get(1,1,n+1,st[x],st[y]+1);
}
assert(z!=0);
int t1=seg[0].get(1,1,n+1,st[x],fn[x]+1)-seg[0].get(1,1,n+1,st[x],st[x]+1);
int t2=seg[0].get(1,1,n+1,st[z],fn[z]+1)-seg[0].get(1,1,n+1,st[z],st[z]+1);
ll v1=seg[1].get(1,1,n+1,st[x],fn[x]+1);
ll v2=seg[1].get(1,1,n+1,st[z],fn[z]+1);
if(ty==1){
int sz1=sz[x]-t1;
int sz2=sz[z]-t2-sz1;
seg[0].up(1,1,n+1,st[x],sz1);
seg[0].up(1,1,n+1,st[z],sz2);
ans*=ferma(comb(sz[z]-t2-1,sz[z]-t2+v2-1,1));
ans%=M;
//cout<<comb(sz[z]-t2-1,sz[z]-t2+v2-1,1)<<" ";
int val1=comb(sz1-1,sz1-1+g[x]-v1,0);
int val2=comb(sz2-1,sz2-1+v2-g[x]+v1,0);
ans*=val1;
ans%=M;
ans*=val2;
ans%=M;
seg[1].up(1,1,n+1,st[x],g[x]-v1-v1);
seg[1].up(1,1,n+1,st[z],0);
ll w=seg[1].get(1,1,n+1,st[z],fn[z]+1);
seg[1].up(1,1,n+1,st[z],g[z]-w-w);
}
else{
int sz1=sz[x]-t1;
int sz2=sz[z]-t2+sz1;
seg[0].up(1,1,n+1,st[x],0);
seg[0].up(1,1,n+1,st[z],sz2);
//cout<<v1<<" "<<v2<<'\n';
ans*=ferma(comb(sz1-1,sz1+v1-1,1));
ans%=M;
ans*=ferma(comb(sz[z]-t2-1,sz[z]-t2+v2-1,1));
ans%=M;
int val1=comb(sz2-1,sz2-1+v2+v1,0);
ans*=val1;
ans%=M;
seg[1].up(1,1,n+1,st[x],0);
seg[1].up(1,1,n+1,st[z],0);
ll w=seg[1].get(1,1,n+1,st[z],fn[z]+1);
seg[1].up(1,1,n+1,st[z],g[z]-w-w);
}
if(bbb){
cout<<0<<'\n';
}
else
cout<<ans<<'\n';
}
return 0;
}
Compilation message
Main.cpp: In member function 'void fnd::add(int, int, int, int, int, int, bool)':
Main.cpp:85:18: error: return-statement with a value, in function returning 'void' [-fpermissive]
85 | if(l>=R)return 0;
| ^
