#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9+7;
const int N = 4e5+10;
const int MAXNC=5e5+10;
const int LG = 20;
vector<int> g[N];
int tin[N], tout[N], tim=0;
int up[N][LG], val[N];
long long fact[MAXNC];
int depth[N], sz[N], used[N];
/*
namespace BIT {
int fen[N];
void add(int at, int vl) {
at++;
while(at < N) {
fen[at] += vl;
at+=at&(-at);
}
}
int query(int at) {
at++;
int res=0;
while(at) {
res+=fen[at];
at-=at&(-at);
}
return res;
}
};
namespace BIT2 {
int fen[N];
void add(int at, int vl) {
at++;
while(at < N) {
fen[at] += vl;
at+=at&(-at);
}
}
int query(int at) {
at++;
int res=0;
while(at) {
res+=fen[at];
at-=at&(-at);
}
return res;
}
};
namespace BIT3 {
int fen[N];
void add(int at, int vl) {
at++;
while(at < N) {
fen[at] += vl;
at+=at&(-at);
}
}
int query(int at) {
at++;
int res=0;
while(at) {
res+=fen[at];
at-=at&(-at);
}
return res;
}
};
void change(int x, int vl) {
BIT::add(tin[x], vl);
BIT::add(tout[x], -vl);
}
int query(int anc, int ch) {
return BIT::query(tin[ch])-BIT::query(tin[anc]);
}
int query2(int l, int r) {
if(l>r)return 0;
if(l == 0)return BIT2::query(r);
return BIT2::query(r)-BIT2::query(l-1);
}
int query3(int l, int r) {
if(l>r)return 0;
if(l == 0)return BIT3::query(r);
return BIT3::query(r)-BIT3::query(l-1);
}
*/
long long binpow(long long a, long long b) {
long long res = 1;
while(b) {
if(b&1) {
res=(res*a)%mod;
}
a=(a*a)%mod;
b>>=1;
}
return res;
}
long long ncr(long long nn, long long rr) {
if(rr > nn)return 0;
if(rr < 0)return 0;
long long res = fact[nn];
res = (res*binpow(fact[rr], mod-2))%mod;
res = (res*binpow(fact[nn-rr], mod-2))%mod;
return res;
}
void dfs(int at, int p) {
sz[at]=1;
up[at][0] = p;
for(int i = 1;i<LG;i++)up[at][i] = up[up[at][i-1]][i-1];
tin[at] = tim++;
for(int to:g[at]) {
if(to == p)continue;
depth[to]=depth[at]+1;
dfs(to, at);
sz[at]+=sz[to];
}
tout[at] = tim++;
}
/*
int findroot(int at) {
for(int i = LG-1;i>=0;i--) {
if(up[at][i] != 0 and query(up[at][i], at) == depth[at]-depth[up[at][i]]) {
at = up[at][i];
}
}
return at;
}
*/
struct ANS {
long long mult = 1;
long long zero = 0;
void add(long long vl) {
if(vl == 0)
zero++;
else
mult = (mult*vl)%mod;
}
void del(long long vl) {
if(vl == 0) {
zero--;
}
else {
mult = (mult*binpow(vl, mod-2))%mod;
}
}
long long get() {
if(zero>0)return 0;
return mult;
}
};
int main () {
cin.tie(0)->sync_with_stdio(0);
fact[0] = 1;
for(int i = 1;i<MAXNC;i++)fact[i] = (fact[i-1]*i)%mod;
int n, r;
cin >> n >> r;
for(int i = 1;i<n;i++) {
int u, v;
cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
dfs(1, 0);
int vv[n+1];
val[1] = r;
used[1] = 1;
// for(int i = 2;i<=n;i++)change(i, 1);
// BIT3::update(tin[1], -n);
// BIT3::update(tout[1], n);
ANS ans;
ans.add(ncr(n+r-1, r));
cout << ans.get() << "\n";
for(int i = 1;i<=n;i++) {
assert(depth[i]*depth[i] <= n*n+10);
}
int q;
cin >> q;
while(q--) {
int t;
cin >> t;
if(t == 1) {
int u, v;
cin >> u >> v;
// val[u] += v;
// vv[u]=v;
// used[u] = 1;
// int par = up[u][0];
// int rr = -1;
// while(1) {
//// if(used[par] == 1) {
//// ans.del(ncr(sz[par]+val[par]-1, val[par]));
//// }
// sz[par] -= sz[u];
// val[par] -= v;
// if(used[par]==1){
//// ans.add(ncr(sz[par]+val[par]-1, val[par]));
// break;
// }
// }
// ans.add(ncr(sz[u]+val[u]-1, val[u]));
}
else {
int u;
cin >> u;
// ans.del(ncr(sz[u]+val[u]-1, val[u]));
// used[u] = 0;
// val[u]-=vv[u];
// int par = up[u][0];
// int rr = -1;
// while(1) {
//// if(used[par] == 1) {
//// ans.del(ncr(sz[par]+val[par]-1, val[par]));
//// }
// sz[par] += sz[u];
// val[par] += vv[u];
// if(used[par]==1){
//// ans.add(ncr(sz[par]+val[par]-1, val[par]));
// break;
// }
// }
}
cout << ans.get() << "\n";
}
}
Compilation message
Main.cpp: In function 'int main()':
Main.cpp:167:7: warning: unused variable 'vv' [-Wunused-variable]
167 | int vv[n+1];
| ^~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
105 ms |
104796 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
5 ms |
19292 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
116 ms |
103172 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
97 ms |
46024 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
105 ms |
104796 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |