#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define bug(x) cout << #x << " : " << x << '\n'
#define ios ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0)
typedef long long ll;
typedef pair<int, int> pii;
const int maxn = 1e6 + 10;
const int maxlg = 19;
const int maxf = 1e6 + 10;
const int mod = 1e9 + 7;
const int inf = 1e9 + 10;
int n, fact[maxf], invfact[maxf];
int val[maxn], tag[maxn];
int par[maxn][maxlg], sz[maxn], st[maxn], ed[maxn], tme = 1;
ll fenC[maxn], fenS[maxn], fenP[maxn];
vector<int> G[maxn];
int add(int a, int b){
int c = a + b;
if(c >= mod) c -= mod;
if(c < 0) c += mod;
return c;
}
int mul(int a, int b){
return 1ll * a * b % mod;
}
int pwr(int a, int b){
int res = 1;
for(; b; b >>= 1, a = mul(a, a)) if(b & 1) res = mul(res, a);
return res;
}
int inv(int a){
return pwr(a, mod - 2);
}
int C(ll a, ll b){
if(a > b)
return 0;
if(b < 0 or b >= maxf){
cout << "-2\n";
exit(0);
}
return mul(fact[b], mul(invfact[a], invfact[b - a]));
}
void update_fact(){
fact[0] = invfact[0] = 1;
for(int i = 1; i < maxf; i ++){
fact[i] = mul(fact[i - 1], i);
invfact[i] = inv(fact[i]);
}
/*
invfact[maxf - 1] = inv(fact[maxf - 1]);
for(int i = maxf - 2; ~i; i --)
invfact[i] = mul(invfact[i + 1], i + 1);
*/
}
void add(ll *fen, int i, ll x){
for(; i <= n; i += i & -i)
fen[i] += x;
}
ll get(ll *fen, int i){
ll res = 0;
for(; i; i -= i & -i)
res += fen[i];
return res;
}
ll get(ll *fen, int l, int r){
return get(fen, r) - get(fen, l - 1);
}
void dfs(int v, int p = 0){
par[v][0] = p;
for(int i = 1; i < maxlg and par[v][i - 1]; i ++)
par[v][i] = par[par[v][i - 1]][i - 1];
st[v] = tme;
sz[v] = 1;
for(int u : G[v]){
if(u ^ p){
tme ++;
dfs(u, v);
sz[v] += sz[u];
}
}
ed[v] = tme;
}
int get_val(int v){
int cnt = sz[v] - get(fenC, st[v] + 1, ed[v]);
ll sum = tag[v] - get(fenS, st[v] + 1, ed[v]);
return C(cnt - 1, cnt + sum - 1);
}
int find(int v){
int x = get(fenP, st[v]);
for(int i = maxlg - 1; ~i; i --){
int u = par[v][i];
if(!u) continue;
if(get(fenP, st[u]) == x)
v = u;
}
return par[v][0];
}
int main(){
ios;
update_fact();
int r;
cin >> n >> r;
for(int i = 0; i < n - 1; i ++){
int u, v;
cin >> u >> v;
G[u].pb(v);
G[v].pb(u);
}
dfs(1);
memset(tag, -1, sizeof tag);
tag[1] = r;
add(fenP, st[1] + 1, 1); add(fenP, ed[1] + 1, -1);
for(int i = 2; i <= n; i ++)
val[i] = 1;
val[1] = get_val(1);
int ans = val[1];
cout << ans << '\n';
int q; cin >> q;
int Cnt = 0;
while(q--){
int t, v;
cin >> t >> v;
if(t == 1){
int x; cin >> x;
tag[v] = x;
val[v] = get_val(v);
if(val[v])
ans = mul(ans, val[v]);
else
Cnt ++;
int cnt = sz[v] - get(fenC, st[v] + 1, ed[v]);
add(fenC, st[v], cnt);
ll sum = tag[v] - get(fenS, st[v] + 1, ed[v]);
add(fenS, st[v], sum);
add(fenP, st[v] + 1, 1); add(fenP, ed[v] + 1, -1);
int p = find(v);
if(inv(val[p]))
ans = mul(ans, inv(val[p]));
else
Cnt --;
val[p] = get_val(p);
if(val[p])
ans = mul(ans, val[p]);
else
Cnt ++;
}
else{
if(inv(val[v]))
ans = mul(ans, inv(val[v]));
else
Cnt --;
val[v] = 1;
int cnt = sz[v] - get(fenC, st[v] + 1, ed[v]);
add(fenC, st[v], -cnt);
ll sum = tag[v] - get(fenS, st[v] + 1, ed[v]);
add(fenS, st[v], -sum);
add(fenP, st[v] + 1, -1); add(fenP, ed[v] + 1, 1);
int p = find(v);
if(inv(val[p]))
ans = mul(ans, inv(val[p]));
else
Cnt --;
val[p] = get_val(p);
if(val[p])
ans = mul(ans, val[p]);
else
Cnt ++;
tag[v] = -1;
}
if(Cnt)
cout << "0\n";
else
cout << ans << '\n';
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
305 ms |
67756 KB |
Output is correct |
2 |
Correct |
299 ms |
67684 KB |
Output is correct |
3 |
Correct |
309 ms |
67652 KB |
Output is correct |
4 |
Correct |
313 ms |
67860 KB |
Output is correct |
5 |
Correct |
291 ms |
63752 KB |
Output is correct |
6 |
Correct |
171 ms |
36104 KB |
Output is correct |
7 |
Correct |
182 ms |
35968 KB |
Output is correct |
8 |
Correct |
178 ms |
35988 KB |
Output is correct |
9 |
Correct |
290 ms |
60148 KB |
Output is correct |
10 |
Correct |
339 ms |
60036 KB |
Output is correct |
11 |
Correct |
302 ms |
60116 KB |
Output is correct |
12 |
Correct |
307 ms |
58832 KB |
Output is correct |
13 |
Correct |
307 ms |
65260 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
176 ms |
35628 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
310 ms |
68588 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
328 ms |
64724 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
305 ms |
67756 KB |
Output is correct |
2 |
Correct |
299 ms |
67684 KB |
Output is correct |
3 |
Correct |
309 ms |
67652 KB |
Output is correct |
4 |
Correct |
313 ms |
67860 KB |
Output is correct |
5 |
Correct |
291 ms |
63752 KB |
Output is correct |
6 |
Correct |
171 ms |
36104 KB |
Output is correct |
7 |
Correct |
182 ms |
35968 KB |
Output is correct |
8 |
Correct |
178 ms |
35988 KB |
Output is correct |
9 |
Correct |
290 ms |
60148 KB |
Output is correct |
10 |
Correct |
339 ms |
60036 KB |
Output is correct |
11 |
Correct |
302 ms |
60116 KB |
Output is correct |
12 |
Correct |
307 ms |
58832 KB |
Output is correct |
13 |
Correct |
307 ms |
65260 KB |
Output is correct |
14 |
Incorrect |
176 ms |
35628 KB |
Output isn't correct |
15 |
Halted |
0 ms |
0 KB |
- |